ggml : guard against sumq2 being 0 in IQ4_NL (ggml-org#20460)

bartowski1182 · web-flow · commit b9da4444dfde · 2026-03-15T10:47:28.000+02:00
diff --git a/ggml/src/ggml-quants.c b/ggml/src/ggml-quants.c
@@ -4767,7 +4767,7 @@ static void quantize_row_iq4_nl_impl(const int super_block_size, const int block
             sumqx += w*q*xb[j];
             sumq2 += w*q*q;
         }
-        d = sumqx/sumq2;
+        d = sumq2 > 0 ? sumqx/sumq2 : 0.f;
         float best = d*sumqx;
         for (int itry = -ntry; itry <= ntry; ++itry) {
             id = (itry + values[0])/max;

Original file line number	Diff line number	Diff line change
`@@ -4767,7 +4767,7 @@ static void quantize_row_iq4_nl_impl(const int super_block_size, const int block`
`4767`	`4767`	`sumqx += wqxb[j];`
`4768`	`4768`	`sumq2 += wqq;`
`4769`	`4769`	`}`
`4770`		`- d = sumqx/sumq2;`
	`4770`	`+ d = sumq2 > 0 ? sumqx/sumq2 : 0.f;`
`4771`	`4771`	`float best = d*sumqx;`
`4772`	`4772`	`for (int itry = -ntry; itry <= ntry; ++itry) {`
`4773`	`4773`	`id = (itry + values[0])/max;`