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Guard against all weights in a super-block being zero #3010

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Merged
merged 2 commits into from
Sep 5, 2023
Merged

Guard against all weights in a super-block being zero #3010

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79f1757
Guard against all weights in a super-block being zero
Kawrakow Sep 4, 2023
2d5f5d7
Also guard against extremely small weights
Kawrakow Sep 4, 2023
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8 changes: 7 additions & 1 deletion k_quants.c
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Original file line number Diff line number Diff line change
Expand Up @@ -83,7 +83,7 @@ static float make_qx_quants(int n, int nmax, const float * restrict x, int8_t *
float ax = fabsf(x[i]);
if (ax > amax) { amax = ax; max = x[i]; }
}
if (!amax) { // all zero
if (amax < 1e-30f) { // all zero
for (int i = 0; i < n; ++i) {
L[i] = 0;
}
Expand Down Expand Up @@ -1086,6 +1086,12 @@ void quantize_row_q6_K_reference(const float * restrict x, block_q6_K * restrict

}

if (!max_abs_scale) {
memset(&y[i], 0, sizeof(block_q6_K));
y[i].d = ggml_fp32_to_fp16(0.f);
continue;
Comment on lines +1091 to +1092
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@ikawrakow

Don't we need to increase x here?

            y[i].d = ggml_fp32_to_fp16(0.f);
            x += QK_K;
            continue;

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Yes, we do. Great catch!

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You will fix it?

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Yup, will push a fix in minute directly to master

}

float iscale = -128.f/max_scale;
y[i].d = ggml_fp32_to_fp16(1/iscale);
for (int ib = 0; ib < QK_K/16; ++ib) {
Expand Down