40 lines
1.4 KiB
C++
40 lines
1.4 KiB
C++
#include <common.h>
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#include <float.h>
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void *quantize_block(void *arguments) {
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// 1. find absmax in block
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// 2. divide input value by absmax to normalize into [-1.0, 1.0]
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// 3. do binary search to find the closest value
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// 4. check minimal distance
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// 5. store index
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struct quantize_block_args *args = (quantize_block_args *) arguments;
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// 1. find absmax in block
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float absmax_block = -FLT_MAX;
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for (long long i = args->block_idx; i < args->block_end; i++)
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absmax_block = fmax(absmax_block, fabs(args->A[i]));
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args->absmax[args->block_idx / args->blocksize] = absmax_block;
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for (long long i = args->block_idx; i < args->block_end; i++) {
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// 2. divide input value by absmax to normalize into [-1.0, 1.0]
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// 3. do binary search to find the closest value
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float normed_value = args->A[i] / absmax_block;
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long long idx = args->bin_searcher->scalar(normed_value);
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// 4. check minimal distance
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// The binary search returns always the value to the left, which might not be the closest value
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if (idx < 255) {
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float dist_left = fabs(normed_value - (args->code[idx]));
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float dist_right = fabs(normed_value - (args->code[idx + 1]));
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if (dist_right < dist_left) { idx += 1; }
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}
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// 5. store index
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args->out[i] = (unsigned char) idx;
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}
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return NULL;
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}
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