mgates3 · Aug 27, 2026 · Aug 6, 2026 · Aug 6, 2026 · Aug 6, 2026 · Aug 7, 2026
diff --git a/config/config.h b/config/config.h
@@ -21,20 +21,38 @@
 
 //------------------------------------------------------------------------------
 #if defined(BLAS_ILP64) || defined(LAPACK_ILP64)
-    typedef int64_t blas_int;
-    typedef int64_t lapack_int;
+    // long is >= 32 bits, long long is >= 64 bits
+    // macOS Accelerate uses long, Intel MKL uses long long,
+    // prefer int64_t (which can be long or long long).
+    #ifdef BLAS_HAVE_ACCELERATE
+        #pragma message "Accelerate ilp64 (long)"
+        #define ACCELERATE_LAPACK_ILP64
+        typedef long blas_int;
+        typedef long lapack_int;
+    #else
+        #pragma message "ilp64 (int64_t)"
+        typedef int64_t blas_int;
+        typedef int64_t lapack_int;
+    #endif
 #else
     typedef int blas_int;
     typedef int lapack_int;
 #endif
 
 //------------------------------------------------------------------------------
-#ifndef BLAS_FORTRAN_STRLEN_END
-#define BLAS_FORTRAN_STRLEN_END
-#endif
+#ifdef BLAS_HAVE_ACCELERATE
+    // Neither old nor new macOS Accelerate API passes strlen.
+    #pragma message "Accelerate undef strlen"
+    #undef BLAS_FORTRAN_STRLEN_END
+    #undef LAPACK_FORTRAN_STRLEN_END
+#else
+    #ifndef BLAS_FORTRAN_STRLEN_END
+    #define BLAS_FORTRAN_STRLEN_END
+    #endif
 
-#ifndef LAPACK_FORTRAN_STRLEN_END
-#define LAPACK_FORTRAN_STRLEN_END
+    #ifndef LAPACK_FORTRAN_STRLEN_END
+    #define LAPACK_FORTRAN_STRLEN_END
+    #endif
 #endif
 
 #endif // CONFIG_H
diff --git a/config/lapack.py b/config/lapack.py
@@ -343,10 +343,31 @@ def blas():
                 inc = '-I' + p + ' ' + define('HAVE_ACCELERATE_CBLAS_H') + ' '
                 break
 
+        flags      = inc + define('HAVE_ACCELERATE')
+        new_lapack = ' -DACCELERATE_NEW_LAPACK'
+        # macOS 13.3, g++ 12.2 requires extra flags to parse Apple's headers.
+        version = ' -mmacosx-version-min=13.3'
+        extra   = ' -flax-vector-conversions'
+
+        choices.append(
+            ['macOS Accelerate (new)',
+             {'LIBS': '-framework Accelerate',
+              'CXXFLAGS': flags + new_lapack }])
+
+        choices.append(
+            ['macOS Accelerate (new, -flax-vector-conversions)',
+             {'LIBS': '-framework Accelerate',
+              'CXXFLAGS': flags + new_lapack + version + extra }])
+
+        choices.append(
+            ['macOS Accelerate (old, pre 13.3)',
+             {'LIBS': '-framework Accelerate',
+              'CXXFLAGS': flags }])
+
         choices.append(
-            ['MacOS Accelerate',
+            ['macOS Accelerate (old, pre 13.3, -flax-vector-conversions)',
              {'LIBS': '-framework Accelerate',
-              'CXXFLAGS': inc + define('HAVE_ACCELERATE')}])
+              'CXXFLAGS': flags + extra }])
     # end
 
     #-------------------- generic -lblas

diff --git a/config/lapack_potrf.cc b/config/lapack_potrf.cc
@@ -8,26 +8,33 @@
 
 #include "config.h"
 
+//------------------------------------------------------------------------------
 #define LAPACK_dpotrf_base FORTRAN_NAME( dpotrf, DPOTRF )
 
-#ifdef __cplusplus
-extern "C"
-#endif
-void LAPACK_dpotrf_base(
-    const char* uplo, const lapack_int* n,
-    double* A, const lapack_int* lda,
-    lapack_int* info
-    #ifdef LAPACK_FORTRAN_STRLEN_END
-    , size_t uplo_len
-    #endif
-    );
-
 #ifdef LAPACK_FORTRAN_STRLEN_END
     #define LAPACK_dpotrf( ... ) LAPACK_dpotrf_base( __VA_ARGS__, 1 )
 #else
     #define LAPACK_dpotrf( ... ) LAPACK_dpotrf_base( __VA_ARGS__ )
 #endif
 
+#ifdef ACCELERATE_NEW_LAPACK
+    #pragma message "include Accelerate.h"
+    #include <stdlib.h>  // workaround
+    #include <Accelerate/Accelerate.h>
+#else
+    #ifdef __cplusplus
+    extern "C"
+    #endif
+    void LAPACK_dpotrf_base(
+        const char* uplo, const lapack_int* n,
+        double* A, const lapack_int* lda,
+        lapack_int* info
+        #ifdef LAPACK_FORTRAN_STRLEN_END
+        , size_t uplo_len
+        #endif
+        );
+#endif
+
 //------------------------------------------------------------------------------
 int main()
 {

diff --git a/config/lapack_pstrf.cc b/config/lapack_pstrf.cc
@@ -8,29 +8,36 @@
 
 #include "config.h"
 
+//------------------------------------------------------------------------------
 #define LAPACK_dpstrf_base FORTRAN_NAME( dpstrf, DPSTRF )
 
-#ifdef __cplusplus
-extern "C"
-#endif
-void LAPACK_dpstrf_base(
-    const char* uplo, const lapack_int* n,
-    double* A, const lapack_int* lda,
-    lapack_int* ipiv, lapack_int* rank,
-    const double* tol,
-    double* work,
-    lapack_int* info
-    #ifdef LAPACK_FORTRAN_STRLEN_END
-    , size_t uplo_len
-    #endif
-    );
-
 #ifdef LAPACK_FORTRAN_STRLEN_END
     #define LAPACK_dpstrf( ... ) LAPACK_dpstrf_base( __VA_ARGS__, 1 )
 #else
     #define LAPACK_dpstrf( ... ) LAPACK_dpstrf_base( __VA_ARGS__ )
 #endif
 
+#ifdef ACCELERATE_NEW_LAPACK
+    #pragma message "include Accelerate.h"
+    #include <stdlib.h>  // workaround
+    #include <Accelerate/Accelerate.h>
+#else
+    #ifdef __cplusplus
+    extern "C"
+    #endif
+    void LAPACK_dpstrf_base(
+        const char* uplo, const lapack_int* n,
+        double* A, const lapack_int* lda,
+        lapack_int* ipiv, lapack_int* rank,
+        const double* tol,
+        double* work,
+        lapack_int* info
+        #ifdef LAPACK_FORTRAN_STRLEN_END
+        , size_t uplo_len
+        #endif
+        );
+#endif
+
 //------------------------------------------------------------------------------
 int main()
 {

diff --git a/config/lapack_version.cc b/config/lapack_version.cc
@@ -9,10 +9,19 @@
 
 #define LAPACK_ilaver FORTRAN_NAME( ilaver, ILAVER )
 
-#ifdef __cplusplus
-extern "C"
+#ifdef ACCELERATE_NEW_LAPACK
+    // A self-declared undecorated prototype would silently bind the legacy
+    // LAPACK 3.2.1 symbol; Apple's header carries the $NEWLAPACK asm-label
+    // decoration on ilaver_.
+    #pragma message "include Accelerate.h"
+    #include <stdlib.h>  // workaround
+    #include <Accelerate/Accelerate.h>
+#else
+    #ifdef __cplusplus
+    extern "C"
+    #endif
+    void LAPACK_ilaver( lapack_int* major, lapack_int* minor, lapack_int* patch );
 #endif
-void LAPACK_ilaver( lapack_int* major, lapack_int* minor, lapack_int* patch );
 
 int main( int argc, char** argv )
 {

diff --git a/include/lapack/config.h b/include/lapack/config.h
@@ -16,8 +16,21 @@
     #define LAPACK_ILP64
 #endif
 
+#ifdef ACCELERATE_NEW_LAPACK
+    // Apple's headers use std::complex in C++ and, for ILP64, `long`
+    // (a distinct type from int64_t == long long on LP64 Darwin).
+    #if defined(__cplusplus) && ! defined(LAPACK_COMPLEX_CPP)
+        #define LAPACK_COMPLEX_CPP
+    #endif
+    #if defined(LAPACK_ILP64) && ! defined(ACCELERATE_LAPACK_ILP64)
+        #define ACCELERATE_LAPACK_ILP64
+    #endif
+#endif
+
 #ifndef lapack_int
-    #ifdef LAPACK_ILP64
+    #if defined(LAPACK_ILP64) && defined(ACCELERATE_NEW_LAPACK)
+        typedef long lapack_int;   // matches Apple's __LAPACK_int
+    #elif defined(LAPACK_ILP64)
         typedef int64_t lapack_int;
     #else
         typedef int lapack_int;
@@ -34,7 +47,8 @@
 // for sdot, slange, clange, etc.
 // LAPACKE's lapack.h is missing #define to protect against multiple
 // definitions, so use lapackpp prefix.
-#if defined(BLAS_HAVE_ACCELERATE) || defined(BLAS_HAVE_F2C)
+#if (defined(BLAS_HAVE_ACCELERATE) && ! defined(ACCELERATE_NEW_LAPACK)) \
+    || defined(BLAS_HAVE_F2C)
     typedef double lapackpp_float_return;
 #else
     typedef float lapackpp_float_return;