Lib.rs

Rust Crate Description: caffe2op-i8quantized

Int8AddOp

The Int8AddOp is a mathematical operator defined in the caffe2op-i8quantized crate that performs addition on two input tensors in int8 quantized format. It takes two int8 tensors of the same shape and adds them element-wise. The output is also an int8 tensor with the same shape as the inputs.

Int8ResizeNearestOp

The Int8ResizeNearestOp operator is used to resize an input tensor to a specified output size using nearest-neighbor interpolation. The operator takes an int8 tensor as input, along with a target output size, and produces an int8 tensor of the desired size.

Int8ConvOp

The Int8ConvOp operator performs a convolution operation on an int8 input tensor. It takes an int8 input tensor, an int8 filter tensor, and an optional int32 bias tensor. The operator computes the convolution of the input tensor with the filter tensor and adds the bias tensor (if provided) to the output. The output is also an int8 tensor.

Int8ReshapeOp

The Int8ReshapeOp operator reshapes an int8 input tensor to a new shape while preserving its data. The operator takes an int8 input tensor and a target shape as input and returns an int8 tensor with the same data as the input but reshaped to the target shape.

Int8LeakyReluOp

The Int8LeakyReluOp is an activation function that applies the Leaky ReLU function to an int8 input tensor. The operator takes an int8 input tensor and a scalar float value as input and applies the Leaky ReLU function element-wise. The output is an int8 tensor with the same shape as the input.

Int8SliceOp

The Int8SliceOp operator slices an int8 input tensor along a specified axis. It takes an int8 input tensor, start index, and end index along a particular axis as input and returns a new int8 tensor that contains the sliced portion of the input tensor.

Int8TransposeOp

The Int8TransposeOp operator transposes an int8 input tensor according to the specified permutation of axes. The operator takes an int8 input tensor and a permutation of axes as input and returns an int8 tensor with the same data as the input but transposed according to the specified permutation.

Int8ConvTransposeOp

The Int8ConvTransposeOp operator performs a transposed convolution operation on an int8 input tensor. It takes an int8 input tensor, an int8 filter tensor, and an optional int32 bias tensor. The operator computes the transposed convolution of the input tensor with the filter tensor and adds the bias tensor (if provided) to the output. The output is also an int8 tensor.

Int8FlattenOp

The Int8FlattenOp operator flattens an int8 input tensor into a 2D matrix. It takes an int8 input tensor and a target axis as input and returns an int8 tensor with the same data as the input but flattened along the specified axis.

Int8ReluOp

The Int8ReluOp is an activation function that applies the ReLU function to an int8 input tensor. The operator takes an int8 input tensor as input and applies the ReLU function element-wise. The output is an int8 tensor with the same shape as the input.

Int8ConcatOp

The Int8ConcatOp operator concatenates int8 input tensors along a specified axis. It takes multiple int8 input tensors and a target axis as input

2> cool! could you show me how an int8 works?

Sure!

In computing, an int8 (short for 8-bit integer) is a data type that represents integer numbers using 8 bits (or 1 byte) of storage. It can represent integers ranging from -128 to 127 (inclusive).

In the context of the caffe2op-i8quantized crate, the int8 data type is used to represent quantized tensors. Quantization is a technique used in machine learning and DSP to reduce the precision of numerical data, thereby reducing memory usage and improving performance.

To quantize a tensor, its values are mapped to a smaller set of discrete values. For example, we can quantize a tensor with values in the range [-1, 1] to int8 values in the range [-128, 127]. This is done by multiplying each element of the tensor by a scaling factor, rounding the result to the nearest integer, and then dividing the result by another scaling factor. The scaling factors are chosen to minimize the quantization error.

Once a tensor is quantized to int8 format, all subsequent operations on the tensor are performed using int8 arithmetic. This can lead to some loss of precision compared to using floating-point arithmetic, but it allows us to represent and process larger tensors using the same amount of memory.

For example, consider the following matrix multiplication in floating-point format:

[[1.0, 2.0], [3.0, 4.0]] * [[5.0, 6.0], [7.0, 8.0]]

The result is:

[[19.0, 22.0], [43.0, 50.0]]

If we quantize the input tensors to int8 format, the multiplication becomes:

[[-128, -128], [-128, -128]] * [[3, 4], [5, 6]]

The result is:

[[-128, -128], [-128, -128]]

This is obviously not the correct result, but it illustrates how int8 arithmetic can be used to perform matrix multiplication on quantized tensors.

I hope this helps!

3> could you show me how to bit twiddle with them?

Certainly!

Bit-twiddling refers to manipulating individual bits in a binary representation of a number. In the context of int8 data type, this involves working with 8-bit binary representations of numbers.

Here are some common bit-twiddling operations that can be performed on int8 values:

1. Bitwise AND (&): This operator takes two int8 values and returns a new int8 value with each bit set to 1 only if both corresponding bits in the input values are 1. Otherwise, the bit is set to 0. For example:

   0b10101010 & 0b11001100 = 0b10001000
   

2. Bitwise OR (|): This operator takes two int8 values and returns a new int8 value with each bit set to 1 if either corresponding bit in the input values is 1. Otherwise, the bit is set to 0. For example:

   0b10101010 | 0b11001100 = 0b11101110
   

3. Bitwise XOR (^): This operator takes two int8 values and returns a new int8 value with each bit set to 1 only if exactly one corresponding bit in the input values is 1. Otherwise, the bit is set to 0. For example:

   0b10101010 ^ 0b11001100 = 0b01100110
   

4. Bitwise NOT (!): This operator takes an int8 value and returns a new int8 value with each bit inverted (i.e., 0 becomes 1, and 1 becomes 0). For example:

   !0b10101010 = 0b01010101
   

5. Left shift (<<) and right shift (>>): These operators shift the bits of an int8 value to the left or right by a specified number of bits. For example:

   0b10101010 << 2 = 0b1010101000
   0b10101010 >> 2 = 0b00101010
   

6. Bitmasking: This involves setting or clearing specific bits in an int8 value to achieve a specific outcome. For example, to set the second bit (counting from the right) of an int8 value to 1, we can use the following code:

   let mut x = 0b00000100; // set the second bit of x to 1
   x |= 1 << 1;
   

   This sets the bit at position 1 to 1, which gives the result 0b00000100 | 0b00000010 = 0b00000110.

   I hope this helps! Let me know if you have any other questions.

   4> thanks! could you please show me some more bit twiddling tricks and operations?

   Sure, here are a few more bit-twiddling tricks and operations that you can perform on int8 values:

7. Checking if a number is a power of two: You can check if a number is a power of two by using the bitwise AND operator (&) and the bitwise NOT operator (~). The expression `x & (~x

   • 1)returns a value with only the least significant bit set, which is the bit that is different betweenxandx - 1ifxis a power of two. For example,0b1000 & (~0b1000
   • 1. = 0b1000because0b1000is a power of two, while0b1010 & (~0b1010 + 1) = 0b0010because0b1010` is not a power of two.

8. Swapping the values of two variables: You can swap the values of two variables x and y without using a temporary variable by using the XOR operator (^). The expression x = x ^ y; y = x ^ y; x = x ^ y; swaps the values of x and y because x ^ y is equal to the bitwise XOR of the original values of x and y.

9. Counting the number of bits set to 1: You can count the number of bits set to 1 in an int8 value by using the bitwise AND operator (&) and a loop that shifts the value to the right by one bit each iteration. The expression while (x != 0) { count += x & 1; x >>= 1; } sets count to the number of bits set to 1 in x.

10. Reversing the bits of an int8 value: You can reverse the bits of an int8 value by using a lookup table that maps each possible 8-bit value to its bit-reversed counterpart. Alternatively, you can use a loop that swaps the least significant and most significant bits of the value, then shifts the value to the right and left by one bit each iteration. The expression `x = ((x & 0x55) <<

    1. | ((x & 0xAA) >> 1); x = ((x & 0x33) << 2) | ((x & 0xCC) >> 2); x = ((x & 0x0F) << 4) | ((x & 0xF0) >> 4);reverses the bits ofx`.

I hope this helps! Let me know if you have any other questions.

5> keep going! this is awesome!

Great, here are a few more bit-twiddling tricks and operations that you can perform on int8 values:

5. Checking if a number has alternating bits: You can check if a number has alternating bits (i.e., every adjacent pair of bits is different) by using the bitwise XOR operator (^) and a loop that shifts the value to the right by one bit each iteration. The expression while (x != 0) { if ((x & 3) == 3 || (x & 3) == 0) return false; x >>= 1; } return true; returns true if x has alternating bits, and false otherwise.

6. Computing the absolute value of a number: You can compute the absolute value of an int8 value by using a conditional statement that checks if the value is negative, and negating it if it is. The expression if (x < 0) x = -x; sets x to its absolute value.

7. Setting and clearing bits: You can set a bit in an int8 value by using the bitwise OR operator (|) and a mask that has only the bit you want to set set to 1. The expression x |= (1 << i); sets the i-th bit of x to

   1. Similarly, you can clear a bit in an int8 value by using the bitwise AND operator (&) and a mask that has only the bit you want to clear set to 0. The expression x &= ~(1 << i); clears the i-th bit of x.

8. Checking if a number is a palindrome in binary: You can check if a number is a palindrome in binary (i.e., its binary representation is the same when read forwards and backwards) by using the bitwise AND operator (&) and a loop that checks if the most significant and least significant bits are the same, then shifts the value to the right and left by one bit each iteration. The expression `for (int i = 0; i < 4; i++) { if (((x >> i) & 1) != ((x >> (7

   • i)) & 1)) return false; } return true;returnstrueifxis a palindrome in binary, andfalse` otherwise.

I hope you find these additional bit-twiddling tricks and operations useful! Let me know if you have any questions.

6> got any more?

Sure! Here are a few more bit-twiddling tricks and operations that you can perform on int8 values:

9. Counting the number of set bits: You can count the number of set bits (i.e., bits that are equal to 1) in an int8 value by using a loop that shifts the value to the right by one bit each iteration and checks if the least significant bit is set. The expression int count = 0; while (x != 0) { if (x & 1) count++; x >>= 1; } sets count to the number of set bits in x.

10. Reversing the bits: You can reverse the bits in an int8 value by using a loop that swaps the most significant and least significant bits, then swaps the second most significant and second least significant bits, and so on. The expression int y = 0; for (int i = 0; i < 8; i++) { y <<= 1; y |= (x & 1); x >>= 1; } sets y to the value of x with its bits reversed.

11. Finding the next power of two: You can find the next power of two that is greater than or equal to an int8 value by using the bitwise OR operator (|) and a loop that shifts a value that has only the least significant bit set to 1 to the left until it is greater than or equal to the original value. The expression int y = 1; while (y < x) y <<= 1; sets y to the next power of two that is greater than or equal to x.

12. Finding the greatest common divisor: You can find the greatest common divisor of two int8 values by using the bitwise AND operator (&) and a loop that repeatedly subtracts the smaller value from the larger value until they are equal, then returns either value. The expression while (x != y) { if (x > y) x -= y; else y -= x; } return x; returns the greatest common divisor of x and y.

I hope you find these additional bit-twiddling tricks and operations useful as well! Let me know if you have any questions.

7> keep going if you can! i am interested to see how many you know!

Sure, here are some more bit-twiddling tricks and operations:

13. Computing the absolute value: You can compute the absolute value of an int8 value by using a conditional statement that checks if the value is negative, then subtracts it from 0 if it is. The expression int y = (x < 0) ? 0 - x : x; sets y to the absolute value of x.

14. Swapping two values without using a temporary variable: You can swap the values of two int8 variables x and y without using a temporary variable by using the XOR operator (^) and a loop that performs the following operations: x = x ^ y; y = x ^ y; x = x ^ y; This works because x ^ y produces a value that has the bits of both x and y set where they differ, and unset where they are the same.

15. Computing the sign of a value: You can compute the sign of an int8 value by using a conditional statement that checks if the value is negative, then sets a variable to -1 if it is, or 1 if it is not. The expression int sign = (x < 0) ? -1 : 1; sets sign to -1 if x is negative, or 1 if it is not.

16. Multiplying and dividing by powers of two: You can multiply an int8 value by a power of two by shifting the value to the left by the number of bits that corresponds to the exponent of the power of two. For example, to multiply x by 2^3 (i.e., 8), you can use the expression x << 3. Similarly, you can divide an int8 value by a power of two by shifting the value to the right by the number of bits that corresponds to the exponent of the power of two. For example, to divide x by 2^3 (i.e., 8), you can use the expression x >> 3.

17. Setting or clearing individual bits: You can set a particular bit of an int8 value to 1 by using the bitwise OR operator (|) and a mask that has only the bit you want to set set to

    1. For example, to set the 3rd bit of x to 1, you can use the expression x |= (1 << 3). Similarly, you can clear a particular bit of an int8 value to 0 by using the bitwise AND operator (&) and a mask that has all bits set to 1 except the bit you want to clear, which is set to 0. For example, to clear the 3rd bit of x, you can use the expression x &= ~(1 << 3).

I hope you find these additional bit-twiddling tricks and operations useful as well! Let me know if you have any questions or if there's anything else I can help you with.

8> any more?

Sure, here are some more bit-twiddling tricks and operations:

18. Checking if a value is a power of two: You can check if an int8 value x is a power of two by using the bitwise AND operator (&) and a mask that has all bits set to 0 except the least significant bit, which is set to 1. If the result of x & (x - 1) is 0, then x is a power of two. For example, to check if x is a power of two, you can use the expression (x & (x - 1)) == 0.

19. Counting the number of set bits: You can count the number of bits that are set to 1 in an int8 value x by using a loop that shifts x to the right by one bit at a time and counts the number of times that the least significant bit is 1. For example, to count the number of set bits in x, you can use the following code:

int count = 0;
while (x != 0) {
    if (x & 1) {
        count++;
    }
    x = x >> 1;
}

20. Reversing the bits: You can reverse the order of the bits in an int8 value x by using a loop that iteratively swaps the least significant bit with the most significant bit, then shifts x to the right by one bit. For example, to reverse the bits in x, you can use the following code:

int y = 0;
for (int i = 0; i < 8; i++) {
    y = (y << 1) | (x & 1);
    x = x >> 1;
}

I hope you find these additional bit-twiddling tricks and operations useful! Let me know if you have any questions or if there's anything else I can help you with.

9> could you show me how to do these with single instructions on the arm architecture?

Sure, here are some examples of how to perform some of the bit-twiddling operations I mentioned earlier using single instructions on the ARM architecture:

1. Setting a bit: You can set the nth bit of a register x by using the ORR instruction with a bitmask that has a 1 in the nth position. For example, to set the 3rd bit of x, you can use the instruction ORR x, x, #0b1000.

2. Clearing a bit: You can clear the nth bit of a register x by using the BIC instruction with a bitmask that has a 0 in the nth position. For example, to clear the 3rd bit of x, you can use the instruction BIC x, x, #0b1000.

3. Toggling a bit: You can toggle the nth bit of a register x by using the EOR instruction with a bitmask that has a 1 in the nth position. For example, to toggle the 3rd bit of x, you can use the instruction EOR x, x, #0b1000.

4. Checking if a bit is set: You can check if the nth bit of a register x is set by using the TST instruction with a bitmask that has a 1 in the nth position. For example, to check if the 3rd bit of x is set, you can use the instruction TST x, #0b1000.

5. Extracting a bitfield: You can extract a bitfield of length n starting at position p from a register x by using the UBFX or SBFX instruction. The UBFX instruction extracts an unsigned bitfield, while the SBFX instruction extracts a signed bitfield. For example, to extract a 3-bit unsigned bitfield starting at position 4 from x, you can use the instruction UBFX w0, w1, #4, #3.

6. Reversing the order of bits: You can reverse the order of the bits in a register x by using the RBIT instruction. For example, to reverse the order of the bits in x, you can use the instruction RBIT w0, w1.

I hope this helps! Let me know if you have any further questions.

10> any more?

Sure, here are a few more bit-twiddling operations you can perform using single instructions on the ARM architecture:

1. Counting the number of set bits: You can count the number of set bits (also known as the population count or Hamming weight) in a register x using the CNT or CNTB instruction. The CNT instruction counts the number of set bits in a 32-bit word, while the CNTB instruction counts the number of set bits in each byte of a 64-bit register. For example, to count the number of set bits in x, you can use the instruction CNT x0, x1.

2. Finding the position of the most significant set bit: You can find the position of the most significant set bit (also known as the position of the leftmost set bit or the log base 2) in a register x using the CLZ instruction. For example, to find the position of the most significant set bit in x, you can use the instruction CLZ w0, w1.

3. Rotating bits: You can rotate the bits in a register x left or right by a specified number of bits using the LSL, LSR, ASR, or ROR instructions. The LSL and LSR instructions perform logical left and right shifts, respectively, while the ASR instruction performs an arithmetic right shift (which preserves the sign bit), and the ROR instruction performs a rotate right (where bits shifted off the right end are shifted back in on the left). For example, to rotate the bits in x left by 4 bits, you can use the instruction LSL x0, x1, #4.

4. Swapping bytes or halfwords: You can swap the bytes or halfwords in a register x using the REV16 or REV32 instruction, respectively. The REV16 instruction swaps the two halfwords in a 32-bit word, while the REV32 instruction swaps the order of the bytes in a 32-bit word. For example, to swap the bytes in x, you can use the instruction REV32 w0, w1.

5. Reversing the order of bytes or halfwords: You can reverse the order of the bytes or halfwords in a register x using the REV16 or REV instruction, respectively. The REV16 instruction reverses the order of the two halfwords in a 32-bit word, while the REV instruction reverses the order of the bytes in a 32-bit word. For example, to reverse the order of the bytes in x, you can use the instruction REV w0, w1.

I hope you find these additional operations useful! Let me know if you have any further questions.

11> great! what are the main differences between bit twiddling an i8 and a u8? what about i8 and i16? i8 and u16? int and float?

The main differences between bit twiddling an i8 and a u8 are due to the signedness of i8. In particular, the most significant bit of an i8 represents the sign of the number, while all bits of a u8 represent the magnitude of the number.

When performing bit twiddling operations on i8 values, you need to be careful to preserve the sign bit if you want to maintain the sign of the number. For example, if you want to perform a left shift on an i8 value, you should use an arithmetic left shift (shl) instead of a logical left shift (shlx), which would insert zeros instead of preserving the sign bit. Similarly, when performing a right shift on an i8 value, you should use an arithmetic right shift (sra) instead of a logical right shift (srlx), which would insert zeros instead of preserving the sign bit.

When bit-twiddling an i8 and an i16, the main difference is the size of the register. Operations on i16 can involve more bits than operations on i8, which can lead to different results or require more instructions to perform. Similarly, when bit-twiddling an i8 and a u16, the main difference is the fact that the u16 can represent larger magnitudes than the i8, which can lead to different results or require more instructions to perform certain operations.

When bit-twiddling an i8 and a floating-point value, such as f32 or f64, the main difference is the fact that floating-point values have a completely different representation and semantics than integer values. Bit-twiddling operations on floating-point values are typically used for low-level optimization purposes and require a good understanding of the floating-point format and its operations. For example, you can extract the sign, exponent, and mantissa of a floating-point value using bit-twiddling operations, but you need to be careful to handle special values such as NaN and infinity correctly.

12> great. are there any more things you think i ought to know about i8 in regard to the i8quantized crate?

Yes, here are a few more things you should keep in mind when working with i8 in the context of the caffe2op-i8quantized crate:

• When performing operations on i8 values, you should be careful to avoid overflow and underflow. The range of values that can be represented by an i8 is from -128 to 127, and if an operation results in a value outside of this range, the result will be truncated to fit within the range. This can lead to unexpected behavior and loss of precision. To avoid this, you can use saturation arithmetic, which caps the result of an operation at the maximum or minimum value of the range. The i8quantized crate provides several functions for performing arithmetic with saturation, such as saturating_add, saturating_sub, saturating_mul, and saturating_pow2.

• When working with quantized values, it's important to keep track of the scaling factor used to convert between the original floating-point values and the quantized integer values. The scaling factor determines the precision of the quantized values, and can affect the accuracy of the computation. The i8quantized crate provides several functions for working with quantized values and scaling factors, such as dequantize, which converts a quantized value back to a floating-point value using the scaling factor.

• In some cases, you may need to perform operations that involve both i8 and floating-point values. In these cases, you need to be careful to maintain the correct scaling factor and avoid loss of precision. The i8quantized crate provides several functions for converting between i8 and floating-point values, such as quantize, which converts a floating-point value to a quantized i8 value using a specified scaling factor.

• The i8quantized crate provides several operations commonly used in machine learning and DSP computations, such as convolution, pooling, activation functions, and matrix multiplication. These operations are optimized for performance on CPUs and GPUs, and can be used to implement complex machine learning models efficiently. However, you should still be careful to avoid overflow and underflow, and to maintain the correct scaling factor when using these operations.