fix partial spectrum index

include/dlaf_c/eigensolver/eigensolver.h

@@ -118,8 +118,8 @@ DLAF_EXTERN_C void dlaf_pssyevd(const char uplo, const int n, float* a, const in
                                 const int descz[9], int* info) DLAF_NOEXCEPT;
 
 // @copydoc dlaf_pssyevd
-/// @param eigenvalues_index_begin index of the first eigenvalue to compute (has to be 0)
-/// @param eigenvalues_index_end index of the last eigenvalue to compute (exclusive)
+/// @param eigenvalues_index_begin index of the first eigenvalue to compute (has to be 1)
+/// @param eigenvalues_index_end index of the last eigenvalue to compute (inclusive)
 DLAF_EXTERN_C void dlaf_pssyevd_partial_spectrum(
     const char uplo, const int n, float* a, const int ia, const int ja, const int desca[9], float* w,
     float* z, const int iz, const int jz, const int descz[9], const SizeType eigenvalues_index_begin,

include/dlaf_c/eigensolver/gen_eigensolver.h

@@ -41,7 +41,7 @@ DLAF_EXTERN_C int dlaf_symmetric_generalized_eigensolver_s(
     const struct DLAF_descriptor dlaf_descz) DLAF_NOEXCEPT;
 
 /// @copydoc dlaf_symmetric_generalized_eigensolver_s
-/// @param eigenvalues_index_begin index of the first eigenvalue to compute
+/// @param eigenvalues_index_begin index of the first eigenvalue to compute (has to be 0)
 /// @param eigenvalues_index_end index of the last eigenvalue to compute (exclusive)
 DLAF_EXTERN_C int dlaf_symmetric_generalized_eigensolver_partial_spectrum_s(
     const int dlaf_context, const char uplo, float* a, const struct DLAF_descriptor dlaf_desca, float* b,
@@ -116,7 +116,7 @@ DLAF_EXTERN_C int dlaf_symmetric_generalized_eigensolver_factorized_s(
     const struct DLAF_descriptor dlaf_descz) DLAF_NOEXCEPT;
 
 /// @copydoc dlaf_symmetric_generalized_eigensolver_factorized_s
-/// @param eigenvalues_index_begin index of the first eigenvalue to compute
+/// @param eigenvalues_index_begin index of the first eigenvalue to compute (has to be 0)
 /// @param eigenvalues_index_end index of the last eigenvalue to compute (exclusive)
 DLAF_EXTERN_C int dlaf_symmetric_generalized_eigensolver_partial_spectrum_factorized_s(
     const int dlaf_context, const char uplo, float* a, const struct DLAF_descriptor dlaf_desca, float* b,
@@ -208,8 +208,8 @@ DLAF_EXTERN_C void dlaf_pssygvd(const char uplo, const int n, float* a, const in
                                 const int descz[9], int* info) DLAF_NOEXCEPT;
 
 /// @copydoc dlaf_pssygvd
-/// @param eigenvalues_index_begin index of the first eigenvalue to compute
-/// @param eigenvalues_index_end index of the last eigenvalue to compute (exclusive)
+/// @param eigenvalues_index_begin index of the first eigenvalue to compute (has to be 1)
+/// @param eigenvalues_index_end index of the last eigenvalue to compute (inclusive)
 DLAF_EXTERN_C void dlaf_pssygvd_partial_spectrum(
     const char uplo, const int n, float* a, const int ia, const int ja, const int desca[9], float* b,
     const int ib, const int jb, const int descb[9], float* w, float* z, const int iz, const int jz,
@@ -303,8 +303,8 @@ DLAF_EXTERN_C void dlaf_pssygvd_factorized(const char uplo, const int n, float*
                                            int* info) DLAF_NOEXCEPT;
 
 /// @copydoc dlaf_pssygvx_factorized
-/// @param eigenvalues_index_begin index of the first eigenvalue to compute
-/// @param eigenvalues_index_end index of the last eigenvalue to compute (exclusive)
+/// @param eigenvalues_index_begin index of the first eigenvalue to compute (has to be 1)
+/// @param eigenvalues_index_end index of the last eigenvalue to compute (inclusive)
 DLAF_EXTERN_C void dlaf_pssygvd_partial_spectrum_factorized(
     const char uplo, const int n, float* a, const int ia, const int ja, const int desca[9], float* b,
     const int ib, const int jb, const int descb[9], float* w, float* z, const int iz, const int jz,

src/c_api/eigensolver/eigensolver.cpp

@@ -83,7 +83,7 @@ int dlaf_hermitian_eigensolver_partial_spectrum_z(
 void dlaf_pssyevd(const char uplo, const int m, float* a, const int ia, const int ja, const int desca[9],
                   float* w, float* z, const int iz, const int jz, const int descz[9],
                   int* info) noexcept {
-  pxheevd<float>(uplo, m, a, ia, ja, desca, w, z, iz, jz, descz, 0l, m, *info);
+  pxheevd<float>(uplo, m, a, ia, ja, desca, w, z, iz, jz, descz, 1l, m, *info);
 }
 
 void dlaf_pssyevd_partial_spectrum(const char uplo, const int m, float* a, const int ia, const int ja,
@@ -97,7 +97,7 @@ void dlaf_pssyevd_partial_spectrum(const char uplo, const int m, float* a, const
 void dlaf_pdsyevd(const char uplo, const int m, double* a, const int ia, const int ja,
                   const int desca[9], double* w, double* z, const int iz, const int jz,
                   const int descz[9], int* info) noexcept {
-  pxheevd<double>(uplo, m, a, ia, ja, desca, w, z, iz, jz, descz, 0l, m, *info);
+  pxheevd<double>(uplo, m, a, ia, ja, desca, w, z, iz, jz, descz, 1l, m, *info);
 }
 
 void dlaf_pdsyevd_partial_spectrum(const char uplo, const int m, double* a, const int ia, const int ja,
@@ -110,7 +110,7 @@ void dlaf_pdsyevd_partial_spectrum(const char uplo, const int m, double* a, cons
 void dlaf_pcheevd(const char uplo, const int m, dlaf_complex_c* a, const int ia, const int ja,
                   const int desca[9], float* w, dlaf_complex_c* z, const int iz, const int jz,
                   const int descz[9], int* info) noexcept {
-  pxheevd<std::complex<float>>(uplo, m, a, ia, ja, desca, w, z, iz, jz, descz, 0l, m, *info);
+  pxheevd<std::complex<float>>(uplo, m, a, ia, ja, desca, w, z, iz, jz, descz, 1l, m, *info);
 }
 
 void dlaf_pcheevd_partial_spectrum(const char uplo, const int m, dlaf_complex_c* a, const int ia,
@@ -125,7 +125,7 @@ void dlaf_pcheevd_partial_spectrum(const char uplo, const int m, dlaf_complex_c*
 void dlaf_pzheevd(const char uplo, const int m, dlaf_complex_z* a, const int ia, const int ja,
                   const int desca[9], double* w, dlaf_complex_z* z, const int iz, const int jz,
                   const int descz[9], int* info) noexcept {
-  pxheevd<std::complex<double>>(uplo, m, a, ia, ja, desca, w, z, iz, jz, descz, 0l, m, *info);
+  pxheevd<std::complex<double>>(uplo, m, a, ia, ja, desca, w, z, iz, jz, descz, 1l, m, *info);
 }
 
 void dlaf_pzheevd_partial_spectrum(const char uplo, const int m, dlaf_complex_z* a, const int ia,

src/c_api/eigensolver/eigensolver.h

@@ -86,12 +86,17 @@ void pxheevd(const char uplo, const int m, T* a, const int ia, const int ja, con
   DLAF_ASSERT(ja == 1, ja);
   DLAF_ASSERT(iz == 1, iz);
   DLAF_ASSERT(iz == 1, iz);
+  DLAF_ASSERT(m > 0 ? eigenvalues_index_begin >= 1 : eigenvalues_index_begin == 1, m,
+              eigenvalues_index_begin);
+  DLAF_ASSERT(m > 0 ? eigenvalues_index_end <= m : eigenvalues_index_end == 0, m, eigenvalues_index_end);
+  DLAF_ASSERT(m > 0 ? eigenvalues_index_begin <= eigenvalues_index_end : true, m,
+              eigenvalues_index_begin, eigenvalues_index_end);
 
   auto dlaf_desca = make_dlaf_descriptor(m, m, ia, ja, desca);
   auto dlaf_descz = make_dlaf_descriptor(m, m, iz, jz, descz);
 
   auto _info = hermitian_eigensolver(desca[1], uplo, a, dlaf_desca, w, z, dlaf_descz,
-                                     eigenvalues_index_begin, eigenvalues_index_end);
+                                     eigenvalues_index_begin - 1, eigenvalues_index_end);
   info = _info;
 }
 

src/c_api/eigensolver/gen_eigensolver.cpp

@@ -175,7 +175,7 @@ int dlaf_hermitian_generalized_eigensolver_partial_spectrum_factorized_z(
 void dlaf_pssygvd(const char uplo, const int m, float* a, const int ia, const int ja, const int desca[9],
                   float* b, const int ib, const int jb, const int descb[9], float* w, float* z,
                   const int iz, const int jz, const int descz[9], int* info) noexcept {
-  pxhegvd<float>(uplo, m, a, ia, ja, desca, b, ib, jb, descb, w, z, iz, jz, descz, 0, m, *info);
+  pxhegvd<float>(uplo, m, a, ia, ja, desca, b, ib, jb, descb, w, z, iz, jz, descz, 1, m, *info);
 }
 
 void dlaf_pssygvd_partial_spectrum(const char uplo, const int m, float* a, const int ia, const int ja,
@@ -191,7 +191,7 @@ void dlaf_pdsygvd(const char uplo, const int m, double* a, const int ia, const i
                   const int desca[9], double* b, const int ib, const int jb, const int descb[9],
                   double* w, double* z, const int iz, const int jz, const int descz[9],
                   int* info) noexcept {
-  pxhegvd<double>(uplo, m, a, ia, ja, desca, b, ib, jb, descb, w, z, iz, jz, descz, 0, m, *info);
+  pxhegvd<double>(uplo, m, a, ia, ja, desca, b, ib, jb, descb, w, z, iz, jz, descz, 1, m, *info);
 }
 
 void dlaf_pdsygvd_partial_spectrum(const char uplo, const int m, double* a, const int ia, const int ja,
@@ -207,7 +207,7 @@ void dlaf_pchegvd(const char uplo, const int m, dlaf_complex_c* a, const int ia,
                   const int desca[9], dlaf_complex_c* b, const int ib, const int jb, const int descb[9],
                   float* w, dlaf_complex_c* z, const int iz, const int jz, const int descz[9],
                   int* info) noexcept {
-  pxhegvd<std::complex<float>>(uplo, m, a, ia, ja, desca, b, ib, jb, descb, w, z, iz, jz, descz, 0, m,
+  pxhegvd<std::complex<float>>(uplo, m, a, ia, ja, desca, b, ib, jb, descb, w, z, iz, jz, descz, 1, m,
                                *info);
 }
 
@@ -225,7 +225,7 @@ void dlaf_pzhegvd(const char uplo, const int m, dlaf_complex_z* a, const int ia,
                   const int desca[9], dlaf_complex_z* b, const int ib, const int jb, const int descb[9],
                   double* w, dlaf_complex_z* z, const int iz, const int jz, const int descz[9],
                   int* info) noexcept {
-  pxhegvd<std::complex<double>>(uplo, m, a, ia, ja, desca, b, ib, jb, descb, w, z, iz, jz, descz, 0, m,
+  pxhegvd<std::complex<double>>(uplo, m, a, ia, ja, desca, b, ib, jb, descb, w, z, iz, jz, descz, 1, m,
                                 *info);
 }
 
@@ -243,7 +243,7 @@ void dlaf_pssygvd_factorized(const char uplo, const int m, float* a, const int i
                              const int desca[9], float* b, const int ib, const int jb,
                              const int descb[9], float* w, float* z, const int iz, const int jz,
                              const int descz[9], int* info) noexcept {
-  pxhegvd_factorized<float>(uplo, m, a, ia, ja, desca, b, ib, jb, descb, w, z, iz, jz, descz, 0, m,
+  pxhegvd_factorized<float>(uplo, m, a, ia, ja, desca, b, ib, jb, descb, w, z, iz, jz, descz, 1, m,
                             *info);
 }
 
@@ -261,7 +261,7 @@ void dlaf_pdsygvd_factorized(const char uplo, const int m, double* a, const int
                              const int desca[9], double* b, const int ib, const int jb,
                              const int descb[9], double* w, double* z, const int iz, const int jz,
                              const int descz[9], int* info) noexcept {
-  pxhegvd_factorized<double>(uplo, m, a, ia, ja, desca, b, ib, jb, descb, w, z, iz, jz, descz, 0, m,
+  pxhegvd_factorized<double>(uplo, m, a, ia, ja, desca, b, ib, jb, descb, w, z, iz, jz, descz, 1, m,
                              *info);
 }
 
@@ -280,7 +280,7 @@ void dlaf_pchegvd_factorized(const char uplo, const int m, dlaf_complex_c* a, co
                              const int descb[9], float* w, dlaf_complex_c* z, const int iz, const int jz,
                              const int descz[9], int* info) noexcept {
   pxhegvd_factorized<std::complex<float>>(uplo, m, a, ia, ja, desca, b, ib, jb, descb, w, z, iz, jz,
-                                          descz, 0, m, *info);
+                                          descz, 1, m, *info);
 }
 
 void dlaf_pchegvd_partial_spectrum_factorized(
@@ -297,7 +297,7 @@ void dlaf_pzhegvd_factorized(const char uplo, const int m, dlaf_complex_z* a, co
                              const int descb[9], double* w, dlaf_complex_z* z, const int iz,
                              const int jz, const int descz[9], int* info) noexcept {
   pxhegvd_factorized<std::complex<double>>(uplo, m, a, ia, ja, desca, b, ib, jb, descb, w, z, iz, jz,
-                                           descz, 0, m, *info);
+                                           descz, 1, m, *info);
 }
 
 void dlaf_pzhegvd_partial_spectrum_factorized(

src/c_api/eigensolver/gen_eigensolver.h

@@ -124,19 +124,24 @@ void pxhegvd(const char uplo, const int m, T* a, const int ia, const int ja, con
   DLAF_ASSERT(jb == 1, jb);
   DLAF_ASSERT(iz == 1, iz);
   DLAF_ASSERT(iz == 1, iz);
+  DLAF_ASSERT(m > 0 ? eigenvalues_index_begin >= 1 : eigenvalues_index_begin == 1, m,
+              eigenvalues_index_begin);
+  DLAF_ASSERT(m > 0 ? eigenvalues_index_end <= m : eigenvalues_index_end == 0, m, eigenvalues_index_end);
+  DLAF_ASSERT(m > 0 ? eigenvalues_index_begin <= eigenvalues_index_end : true, m,
+              eigenvalues_index_begin, eigenvalues_index_end);
 
   auto dlaf_desca = make_dlaf_descriptor(m, m, ia, ja, desca);
   auto dlaf_descb = make_dlaf_descriptor(m, m, ib, jb, descb);
   auto dlaf_descz = make_dlaf_descriptor(m, m, iz, jz, descz);
 
   if (!factorized) {
-    info =
-        hermitian_generalized_eigensolver<T>(desca[1], uplo, a, dlaf_desca, b, dlaf_descb, w, z,
-                                             dlaf_descz, eigenvalues_index_begin, eigenvalues_index_end);
+    info = hermitian_generalized_eigensolver<T>(desca[1], uplo, a, dlaf_desca, b, dlaf_descb, w, z,
+                                                dlaf_descz, eigenvalues_index_begin - 1,
+                                                eigenvalues_index_end);
   }
   else {
     info = hermitian_generalized_eigensolver_factorized<T>(desca[1], uplo, a, dlaf_desca, b, dlaf_descb,
-                                                           w, z, dlaf_descz, eigenvalues_index_begin,
+                                                           w, z, dlaf_descz, eigenvalues_index_begin - 1,
                                                            eigenvalues_index_end);
   }
 }

test/unit/c_api/eigensolver/test_eigensolver_c_api.cpp

@@ -188,34 +188,43 @@ void testEigensolver(const blas::Uplo uplo, const SizeType m, const SizeType mb,
       int desc_a[] = {1, dlaf_context, (int) m, (int) m, (int) mb, (int) mb, 0, 0, lld_a};
       int desc_z[] = {1, dlaf_context, (int) m, (int) m, (int) mb, (int) mb, 0, 0, lld_eigenvectors};
       int info = -1;
+
+      // Treat special case when eval_idx_end is 0 for the C API
+      // The ScaLAPACK API uses base 1 indexing
+      const SizeType eval_idx_end_scalapack = m > 0 && eval_idx_end == 0 ? 1 : eval_idx_end;
+
       if constexpr (std::is_same_v<T, double>) {
         if (eigenvalues_index_end.has_value())
           C_dlaf_pdsyevd_partial_spectrum(dlaf_uplo, (int) m, local_a_ptr, 1, 1, desc_a, eigenvalues_ptr,
-                                          local_eigenvectors_ptr, 1, 1, desc_z, 0, eval_idx_end, &info);
+                                          local_eigenvectors_ptr, 1, 1, desc_z, 1,
+                                          eval_idx_end_scalapack, &info);
         else
           C_dlaf_pdsyevd(dlaf_uplo, (int) m, local_a_ptr, 1, 1, desc_a, eigenvalues_ptr,
                          local_eigenvectors_ptr, 1, 1, desc_z, &info);
       }
       else if constexpr (std::is_same_v<T, float>) {
         if (eigenvalues_index_end.has_value())
           C_dlaf_pssyevd_partial_spectrum(dlaf_uplo, (int) m, local_a_ptr, 1, 1, desc_a, eigenvalues_ptr,
-                                          local_eigenvectors_ptr, 1, 1, desc_z, 0, eval_idx_end, &info);
+                                          local_eigenvectors_ptr, 1, 1, desc_z, 1,
+                                          eval_idx_end_scalapack, &info);
         else
           C_dlaf_pssyevd(dlaf_uplo, (int) m, local_a_ptr, 1, 1, desc_a, eigenvalues_ptr,
                          local_eigenvectors_ptr, 1, 1, desc_z, &info);
       }
       else if constexpr (std::is_same_v<T, std::complex<double>>) {
         if (eigenvalues_index_end.has_value())
           C_dlaf_pzheevd_partial_spectrum(dlaf_uplo, (int) m, local_a_ptr, 1, 1, desc_a, eigenvalues_ptr,
-                                          local_eigenvectors_ptr, 1, 1, desc_z, 0, eval_idx_end, &info);
+                                          local_eigenvectors_ptr, 1, 1, desc_z, 1,
+                                          eval_idx_end_scalapack, &info);
         else
           C_dlaf_pzheevd(dlaf_uplo, (int) m, local_a_ptr, 1, 1, desc_a, eigenvalues_ptr,
                          local_eigenvectors_ptr, 1, 1, desc_z, &info);
       }
       else if constexpr (std::is_same_v<T, std::complex<float>>) {
         if (eigenvalues_index_end.has_value())
           C_dlaf_pcheevd_partial_spectrum(dlaf_uplo, (int) m, local_a_ptr, 1, 1, desc_a, eigenvalues_ptr,
-                                          local_eigenvectors_ptr, 1, 1, desc_z, 0, eval_idx_end, &info);
+                                          local_eigenvectors_ptr, 1, 1, desc_z, 1,
+                                          eval_idx_end_scalapack, &info);
         else
           C_dlaf_pcheevd(dlaf_uplo, (int) m, local_a_ptr, 1, 1, desc_a, eigenvalues_ptr,
                          local_eigenvectors_ptr, 1, 1, desc_z, &info);