Fix bounds checking in dgemv and sgemv, add corresponding tests

Co-authored-by: Quafadas <[email protected]>

Author: Copilot

blas/src/main/java/dev/ludovic/netlib/blas/AbstractBLAS.java

@@ -349,7 +349,7 @@ public void dgemv(String trans, int m, int n, double alpha, double[] a, int offs
     requireNonNull(a);
     requireNonNull(x);
     requireNonNull(y);
-    checkIndex(offseta + n * lda - 1, a.length);
+    checkIndex(offseta + (n - 1) * lda + (m - 1), a.length);
     checkIndex(offsetx + ((lsame("N", trans) ? n : m) - 1) * Math.abs(incx), x.length);
     checkIndex(offsety + ((lsame("N", trans) ? m : n) - 1) * Math.abs(incy), y.length);
     dgemvK(trans, m, n, alpha, a, offseta, lda, x, offsetx, incx, beta, y, offsety, incy);
@@ -377,7 +377,7 @@ public void sgemv(String trans, int m, int n, float alpha, float[] a, int offset
     requireNonNull(a);
     requireNonNull(x);
     requireNonNull(y);
-    checkIndex(offseta + n * lda - 1, a.length);
+    checkIndex(offseta + (n - 1) * lda + (m - 1), a.length);
     checkIndex(offsetx + ((lsame("N", trans) ? n : m) - 1) * Math.abs(incx), x.length);
     checkIndex(offsety + ((lsame("N", trans) ? m : n) - 1) * Math.abs(incy), y.length);
     sgemvK(trans, m, n, alpha, a, offseta, lda, x, offsetx, incx, beta, y, offsety, incy);

blas/src/test/java/dev/ludovic/netlib/blas/DgemvTest.java

@@ -128,4 +128,25 @@ void testSanity(BLAS blas) {
         // }
         assertArrayEquals(expected, dYcopy, depsilon);
     }
+
+    @ParameterizedTest
+    @MethodSource("BLASImplementations")
+    void testOffsetBoundsChecking(BLAS blas) {
+        // Test case that reproduces the original bounds checking issue for dgemv
+        // Matrix A (2x3) with offset=1, stored in array of length 9
+        double[] a = {1.0, 4.0, 7.0, 2.0, 5.0, 8.0, 3.0, 6.0, 9.0};
+        double[] x = {1.0, 2.0, 3.0};
+        double[] y = new double[2];
+        double[] yExpected = new double[2];
+
+        // This should not throw IndexOutOfBoundsException
+        assertDoesNotThrow(() -> {
+            blas.dgemv("N", 2, 3, 1.0, a, 1, 3, x, 0, 1, 0.0, y, 0, 1);
+        });
+
+        // Compare with F2J result
+        f2j.dgemv("N", 2, 3, 1.0, a, 1, 3, x, 0, 1, 0.0, yExpected, 0, 1);
+        blas.dgemv("N", 2, 3, 1.0, a, 1, 3, x, 0, 1, 0.0, y, 0, 1);
+        assertArrayEquals(yExpected, y, depsilon);
+    }
 }

blas/src/test/java/dev/ludovic/netlib/blas/SgemvTest.java

@@ -93,4 +93,25 @@ void testSanity(BLAS blas) {
         blas.sgemv("T", M, N,  1.0f, sgeA, M, sX, 1,  0.0f, sYcopy = sY.clone(), 1);
         assertArrayEquals(expected, sYcopy, sepsilon);
     }
+
+    @ParameterizedTest
+    @MethodSource("BLASImplementations")
+    void testOffsetBoundsChecking(BLAS blas) {
+        // Test case that reproduces the original bounds checking issue for sgemv
+        // Matrix A (2x3) with offset=1, stored in array of length 9
+        float[] a = {1.0f, 4.0f, 7.0f, 2.0f, 5.0f, 8.0f, 3.0f, 6.0f, 9.0f};
+        float[] x = {1.0f, 2.0f, 3.0f};
+        float[] y = new float[2];
+        float[] yExpected = new float[2];
+
+        // This should not throw IndexOutOfBoundsException
+        assertDoesNotThrow(() -> {
+            blas.sgemv("N", 2, 3, 1.0f, a, 1, 3, x, 0, 1, 0.0f, y, 0, 1);
+        });
+
+        // Compare with F2J result
+        f2j.sgemv("N", 2, 3, 1.0f, a, 1, 3, x, 0, 1, 0.0f, yExpected, 0, 1);
+        blas.sgemv("N", 2, 3, 1.0f, a, 1, 3, x, 0, 1, 0.0f, y, 0, 1);
+        assertArrayEquals(yExpected, y, sepsilon);
+    }
 }