BallisticLA · rileyjmurray · Mar 7, 2026 · Mar 7, 2026 · Mar 7, 2026 · Mar 8, 2026
diff --git a/.github/workflows/builtin-blas-macos.yml b/.github/workflows/builtin-blas-macos.yml
@@ -0,0 +1,53 @@
+name: builtin-blas-macos
+on:
+  pull_request:
+  workflow_dispatch:
+
+jobs:
+  build:
+    runs-on: macos-latest
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: configure OS
+        run: |
+          # os level stuff
+          set -x
+          brew install googletest
+
+      - name: install Random123
+        run: |
+          cd ..
+          git clone https://github.com/DEShawResearch/Random123.git
+          cd Random123/
+          mkdir -p `pwd`/../Random123-install/include
+          cp -rp include/Random123 `pwd`/../Random123-install/include/
+
+      - name: build and test RandBLAS (release)
+        run: |
+          cd ..
+          mkdir RandBLAS-build
+          cd RandBLAS-build
+          cmake -DCMAKE_BUILD_TYPE=Release \
+            -DRandBLAS_BLAS_BACKEND=builtin \
+            -DRandom123_DIR=`pwd`/../Random123-install/include/ \
+            -DCMAKE_INSTALL_PREFIX=`pwd`/../RandBLAS-install \
+            -DCMAKE_BINARY_DIR=`pwd` \
+            `pwd`/../RandBLAS
+          make -j2 install
+          ctest --output-on-failure
+
+      - name: build and test RandBLAS (Debug/asan)
+        run: |
+          cd ..
+          mkdir RandBLAS-asan-build
+          cd RandBLAS-asan-build
+          cmake -DCMAKE_BUILD_TYPE=Debug \
+            -DSANITIZE_ADDRESS=ON \
+            -DRandBLAS_BLAS_BACKEND=builtin \
+            -DRandom123_DIR=`pwd`/../Random123-install/include/ \
+            -DCMAKE_INSTALL_PREFIX=`pwd`/../RandBLAS-install \
+            -DCMAKE_BINARY_DIR=`pwd` \
+            `pwd`/../RandBLAS
+          make -j2 install
+          ctest --output-on-failure
diff --git a/CMake/MKL_sparse.cmake b/CMake/MKL_sparse.cmake
@@ -5,6 +5,13 @@ features while still using MKL through BLAS++." ON)
 
 message(STATUS "Checking for MKL sparse BLAS ...")
 
+if (NOT RandBLAS_HAS_BLASPP)
+    message(STATUS "  Disabled: builtin BLAS backend does not support MKL sparse")
+    set(RandBLAS_HAS_MKL FALSE CACHE BOOL "Set if MKL sparse BLAS is available" FORCE)
+    message(STATUS "Checking for MKL sparse BLAS ... ${RandBLAS_HAS_MKL}")
+    return()
+endif()
+
 if (NOT RandBLAS_USE_MKL_SPARSE)
     message(STATUS "  Disabled by user (RandBLAS_USE_MKL_SPARSE=OFF)")
     set(RandBLAS_HAS_MKL FALSE CACHE BOOL "Set if MKL sparse BLAS is available" FORCE)

diff --git a/CMake/RandBLASConfig.cmake.in b/CMake/RandBLASConfig.cmake.in
@@ -8,11 +8,14 @@ set(RandBLAS_VERSION_PATCH "@RandBLAS_VERSION_PATCH@")
 set(RandBLAS_COMMITS_SINCE_RELEASE "@RandBLAS_COMMITS_SINCE_RELEASE@")
 set(RandBLAS_COMMIT_HASH "@RandBLAS_COMMIT_HASH@")
 
-# BLAS++
-if (NOT blaspp_DIR)
-    set(blaspp_DIR @blaspp_DIR@)
+# BLAS backend
+set(RandBLAS_HAS_BLASPP @RandBLAS_HAS_BLASPP@)
+if (RandBLAS_HAS_BLASPP)
+    if (NOT blaspp_DIR)
+        set(blaspp_DIR @blaspp_DIR@)
+    endif ()
+    find_dependency(blaspp)
 endif ()
-find_dependency(blaspp)
 
 # Random123
 if (NOT Random123_DIR)

diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -9,8 +9,24 @@ enable_testing()
 include(rb_build_options)
 include(rb_version)
 
+# Select BLAS backend
+set(RandBLAS_BLAS_BACKEND "blaspp" CACHE STRING
+    "BLAS backend: 'blaspp' (requires BLAS++) or 'builtin' (RandBLAS built-in)")
+set_property(CACHE RandBLAS_BLAS_BACKEND PROPERTY STRINGS blaspp builtin)
+
 # find dependencies
-find_package(blaspp REQUIRED)
+if(RandBLAS_BLAS_BACKEND STREQUAL "blaspp")
+    find_package(blaspp REQUIRED)
+    set(RandBLAS_HAS_BLASPP TRUE CACHE BOOL "Set if using BLAS++ backend" FORCE)
+    message(STATUS "BLAS backend: blaspp")
+elseif(RandBLAS_BLAS_BACKEND STREQUAL "builtin")
+    set(RandBLAS_HAS_BLASPP FALSE CACHE BOOL "Set if using BLAS++ backend" FORCE)
+    message(STATUS "BLAS backend: builtin (RandBLAS built-in)")
+else()
+    message(FATAL_ERROR "Unknown RandBLAS_BLAS_BACKEND='${RandBLAS_BLAS_BACKEND}'. "
+            "Valid values: blaspp, builtin")
+endif()
+
 find_package(Random123 REQUIRED)
 #include(Random123)
 include(OpenMP)

diff --git a/INSTALL.md b/INSTALL.md
@@ -100,14 +100,6 @@ make -j install  # might need "sudo make -j install"
 ctest  # run unit tests (only if GTest was found by CMake)
 ```
 
-If you're running macOS, then it may be necessary to specify
-an additional flag to CMake
-```shell
-     -DCMAKE_CXX_FLAGS="-D __APPLE__"
-```
-This flag is needed to avoid compiler errors with the "sincosf" and "sincos"
-functions in "random_gen.hh".
-
 Here are the conceptual meanings of the recipe's other build flags:
 
 * `-Dblaspp_DIR=X` means `X` is the directory containing the file `blasppConfig.cmake`.
@@ -160,9 +152,3 @@ If performance matters to you then you should inspect the
 information that's printed to screen when you run ``cmake`` for the BLAS++ installation.
 Save that information somewhere while you're setting up your RandBLAS
 development environment.
-
-[An earlier version](https://github.com/BallisticLA/RandBLAS/blob/9d0a03fa41fd7c126b252002a54c2f2562fae31a/INSTALL.md#5-tips)
-of this installation guide had specific recommendations for configuring BLAS++ and LAPACK++ on Intel machines.
-Those recommendations may be useful to you if you're having a hard time getting these libraries setup correctly.
-We removed those recommendations from this guide, since they encouraged a somewhat bad practice of installing BLAS++
-and LAPACK++ to a system-wide location (under ``/opt/``) instead of a location that's used for one project.
diff --git a/RandBLAS/CMakeLists.txt b/RandBLAS/CMakeLists.txt
@@ -1,5 +1,8 @@
 
-set(RandBLAS_libs blaspp Random123)
+set(RandBLAS_libs Random123)
+if (RandBLAS_HAS_BLASPP)
+    list(PREPEND RandBLAS_libs blaspp)
+endif()
 if (RandBLAS_HAS_OpenMP)
     list(APPEND RandBLAS_libs OpenMP::OpenMP_CXX)
 endif()

diff --git a/RandBLAS/base.hh b/RandBLAS/base.hh
@@ -34,18 +34,17 @@
 #include "RandBLAS/config.h"
 #include "RandBLAS/random_gen.hh"
 
-#include <blas.hh>
+#include "RandBLAS/blas_facade.hh"
 #include <utility>
 #include <cstring>
 #include <cstdint>
 #include <iostream>
+#include <sstream>
 
 #if defined(RandBLAS_HAS_OpenMP)
 #include <omp.h>
 #endif
 
-#include<iostream>
-
 
 /// code common across the project
 namespace RandBLAS {

diff --git a/RandBLAS/blas_backend/builtin.hh b/RandBLAS/blas_backend/builtin.hh
@@ -0,0 +1,45 @@
+// Copyright, 2024. See LICENSE for copyright holder information.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are met:
+//
+// (1) Redistributions of source code must retain the above copyright notice,
+// this list of conditions and the following disclaimer.
+//
+// (2) Redistributions in binary form must reproduce the above copyright
+// notice, this list of conditions and the following disclaimer in the
+// documentation and/or other materials provided with the distribution.
+//
+// (3) Neither the name of the copyright holder nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+// POSSIBILITY OF SUCH DAMAGE.
+
+#pragma once
+
+/// @file
+///
+/// Aggregating header for RandBLAS' built-in blas:: implementations.
+/// Provides the enumerations and routines used by RandBLAS when BLAS++ is
+/// not available:
+///   Enumerations: Layout, Op, Uplo, Diag, Side
+///   Level 1:      scal, copy, axpy, dot, nrm2
+///   Level 2:      gemv, ger
+///   Level 3:      gemm, syrk, symm, trmm, trsm
+
+#include "RandBLAS/blas_backend/enums.hh"
+#include "RandBLAS/blas_backend/level1.hh"
+#include "RandBLAS/blas_backend/gemm.hh"
+#include "RandBLAS/blas_backend/level2.hh"
+#include "RandBLAS/blas_backend/level3.hh"
diff --git a/RandBLAS/blas_backend/enums.hh b/RandBLAS/blas_backend/enums.hh
@@ -0,0 +1,49 @@
+// Copyright, 2024. See LICENSE for copyright holder information.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are met:
+//
+// (1) Redistributions of source code must retain the above copyright notice,
+// this list of conditions and the following disclaimer.
+//
+// (2) Redistributions in binary form must reproduce the above copyright
+// notice, this list of conditions and the following disclaimer in the
+// documentation and/or other materials provided with the distribution.
+//
+// (3) Neither the name of the copyright holder nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+// POSSIBILITY OF SUCH DAMAGE.
+
+#pragma once
+
+/// @file
+///
+/// blas:: enum types used by RandBLAS' built-in BLAS backend.
+/// Values match BLAS++ and standard CBLAS character codes, so code compiled
+/// with either backend agrees on the underlying representation.
+
+namespace blas {
+
+// ---------------------------------------------------------------------------
+// Enumerations (values match BLAS++ / standard CBLAS character codes)
+// ---------------------------------------------------------------------------
+
+enum class Layout : char { ColMajor = 'C', RowMajor = 'R' };
+enum class Op     : char { NoTrans = 'N', Trans = 'T', ConjTrans = 'C' };
+enum class Uplo   : char { Upper = 'U', Lower = 'L' };
+enum class Diag   : char { NonUnit = 'N', Unit = 'U' };
+enum class Side   : char { Left = 'L', Right = 'R' };
+
+} // namespace blas