GPU: Add BLAS-1 ops, DeviceScalar, device-resident SpMV, and CG interop (5/5)

Add the operator interface needed for GPU iterative solvers:

- BLAS Level-1 on DeviceMatrix: dot(), norm(), squaredNorm(), setZero(),
  noalias(), operator+=/-=/\*= dispatching to cuBLAS axpy/scal/dot/nrm2.
- DeviceScalar<Scalar>: device-resident scalar returned by reductions.
  Defers host sync until value is read (implicit conversion). Device-side
  division via NPP for real types.
- GpuContext: stream-borrowing constructor, setThreadLocal(), cublasLtHandle(),
  cusparseHandle().
- GEMM upgraded from cublasGemmEx to cublasLtMatmul with heuristic algorithm
  selection and plan caching.
- GpuSparseContext: GpuContext& constructor for same-stream execution,
  deviceView() returning DeviceSparseView with operator* for device-resident
  SpMV (d_y = d_A * d_x).
- geam expressions: d_C = d_A + alpha * d_B via cublasXgeam.
- GpuSVD::matrixV() convenience wrapper.

These additions make DeviceMatrix usable as a VectorType in Eigen algorithm
templates. Conjugate gradient is the motivating example and is tested against
CPU ConjugateGradient for correctness.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
This commit is contained in:
Rasmus Munk Larsen
2026-04-09 19:54:13 -07:00
parent 43a95b62bb
commit 014f12f11a
22 changed files with 3363 additions and 151 deletions

View File

@@ -12,6 +12,7 @@
#define EIGEN_USE_GPU
#include "main.h"
#include <Eigen/Sparse>
#include <Eigen/GPU>
using namespace Eigen;
@@ -230,6 +231,217 @@ void test_scalar() {
CALL_SUBTEST(test_move_assign<Scalar>(64, 64));
}
// ---- BLAS-1: dot product ----------------------------------------------------
template <typename Scalar>
void test_blas1(Index n) {
using Vec = Matrix<Scalar, Dynamic, 1>;
using RealScalar = typename NumTraits<Scalar>::Real;
// All BLAS-1 ops share one GpuContext — same stream, zero event overhead.
GpuContext ctx;
RealScalar tol = RealScalar(10) * RealScalar(n) * NumTraits<Scalar>::epsilon();
// dot
{
Vec a = Vec::Random(n);
Vec b = Vec::Random(n);
auto d_a = DeviceMatrix<Scalar>::fromHost(a, ctx.stream());
auto d_b = DeviceMatrix<Scalar>::fromHost(b, ctx.stream());
Scalar gpu_dot = d_a.dot(ctx, d_b);
Scalar cpu_dot = a.dot(b);
VERIFY(numext::abs(gpu_dot - cpu_dot) < tol * numext::abs(cpu_dot) + tol);
}
// norm / squaredNorm
{
Vec a = Vec::Random(n);
auto d_a = DeviceMatrix<Scalar>::fromHost(a, ctx.stream());
RealScalar gpu_norm = d_a.norm(ctx);
RealScalar cpu_norm = a.norm();
VERIFY(numext::abs(gpu_norm - cpu_norm) < tol * cpu_norm + tol);
RealScalar gpu_sqnorm = d_a.squaredNorm(ctx);
RealScalar cpu_sqnorm = a.squaredNorm();
VERIFY(numext::abs(gpu_sqnorm - cpu_sqnorm) < tol * cpu_sqnorm + tol);
}
// addScaled (axpy)
{
Vec x = Vec::Random(n);
Vec y = Vec::Random(n);
Scalar alpha(2.5);
Vec y_ref = y + alpha * x;
auto d_y = DeviceMatrix<Scalar>::fromHost(y, ctx.stream());
auto d_x = DeviceMatrix<Scalar>::fromHost(x, ctx.stream());
d_y.addScaled(ctx, alpha, d_x);
Vec y_gpu = d_y.toHost(ctx.stream());
VERIFY((y_gpu - y_ref).norm() < tol * y_ref.norm() + tol);
}
// scale (scal)
{
Vec x = Vec::Random(n);
Scalar alpha(3.0);
Vec x_ref = alpha * x;
auto d_x = DeviceMatrix<Scalar>::fromHost(x, ctx.stream());
d_x.scale(ctx, alpha);
Vec x_gpu = d_x.toHost(ctx.stream());
VERIFY((x_gpu - x_ref).norm() < tol * x_ref.norm() + tol);
}
// copyFrom
{
Vec x = Vec::Random(n);
auto d_x = DeviceMatrix<Scalar>::fromHost(x, ctx.stream());
DeviceMatrix<Scalar> d_y;
d_y.copyFrom(ctx, d_x);
Vec y = d_y.toHost(ctx.stream());
VERIFY_IS_APPROX(y, x);
}
// setZero
{
Vec x = Vec::Random(n);
auto d_x = DeviceMatrix<Scalar>::fromHost(x, ctx.stream());
d_x.setZero(ctx);
Vec result = d_x.toHost(ctx.stream());
VERIFY_IS_EQUAL(result, Vec::Zero(n));
}
}
// ---- BLAS-1 operator overloads (CG-style) -----------------------------------
template <typename Scalar>
void test_cg_operators(Index n) {
using Vec = Matrix<Scalar, Dynamic, 1>;
using RealScalar = typename NumTraits<Scalar>::Real;
RealScalar tol = RealScalar(10) * RealScalar(n) * NumTraits<Scalar>::epsilon();
Vec x = Vec::Random(n);
Vec p = Vec::Random(n);
Vec tmp = Vec::Random(n);
Vec z = Vec::Random(n);
Scalar alpha(2.5);
Scalar beta(0.7);
// Test: x += alpha * p
{
Vec x_ref = x + alpha * p;
auto d_x = DeviceMatrix<Scalar>::fromHost(x);
auto d_p = DeviceMatrix<Scalar>::fromHost(p);
d_x += alpha * d_p;
Vec x_gpu = d_x.toHost();
VERIFY((x_gpu - x_ref).norm() < tol * x_ref.norm() + tol);
}
// Test: r -= alpha * tmp
{
Vec r = Vec::Random(n);
Vec r_ref = r - alpha * tmp;
auto d_r = DeviceMatrix<Scalar>::fromHost(r);
auto d_tmp = DeviceMatrix<Scalar>::fromHost(tmp);
d_r -= alpha * d_tmp;
Vec r_gpu = d_r.toHost();
VERIFY((r_gpu - r_ref).norm() < tol * r_ref.norm() + tol);
}
// Test: p = z + beta * p (cuBLAS geam)
{
Vec p_copy = p;
Vec p_ref = z + beta * p_copy;
auto d_p = DeviceMatrix<Scalar>::fromHost(p_copy);
auto d_z = DeviceMatrix<Scalar>::fromHost(z);
d_p = d_z + beta * d_p;
Vec p_gpu = d_p.toHost();
VERIFY((p_gpu - p_ref).norm() < tol * p_ref.norm() + tol);
}
// Test: operator+= and operator-= with DeviceMatrix (no scalar)
{
Vec a = Vec::Random(n);
Vec b = Vec::Random(n);
Vec a_ref = a + b;
auto d_a = DeviceMatrix<Scalar>::fromHost(a);
auto d_b = DeviceMatrix<Scalar>::fromHost(b);
d_a += d_b;
VERIFY((d_a.toHost() - a_ref).norm() < tol * a_ref.norm() + tol);
}
}
// ---- DeviceScalar: deferred sync -------------------------------------------
template <typename Scalar>
void test_device_scalar() {
using Vec = Matrix<Scalar, Dynamic, 1>;
using RealScalar = typename NumTraits<Scalar>::Real;
const Index n = 256;
Vec a = Vec::Random(n);
Vec b = Vec::Random(n);
GpuContext ctx;
auto d_a = DeviceMatrix<Scalar>::fromHost(a, ctx.stream());
auto d_b = DeviceMatrix<Scalar>::fromHost(b, ctx.stream());
// dot() returns DeviceScalar — implicit conversion to Scalar syncs.
Scalar gpu_dot = d_a.dot(ctx, d_b);
Scalar cpu_dot = a.dot(b);
RealScalar tol = RealScalar(10) * RealScalar(n) * NumTraits<Scalar>::epsilon();
VERIFY(numext::abs(gpu_dot - cpu_dot) < tol * numext::abs(cpu_dot) + tol);
// squaredNorm() returns host RealScalar directly (syncs internally).
RealScalar gpu_sqnorm = d_a.squaredNorm(ctx);
RealScalar cpu_sqnorm = a.squaredNorm();
VERIFY(numext::abs(gpu_sqnorm - cpu_sqnorm) < tol * cpu_sqnorm + tol);
// norm() returns DeviceScalar<RealScalar> — implicit conversion syncs.
RealScalar gpu_norm = d_a.norm(ctx);
RealScalar cpu_norm = a.norm();
VERIFY(numext::abs(gpu_norm - cpu_norm) < tol * cpu_norm + tol);
// Convenience overloads (thread-local context).
GpuContext::setThreadLocal(&ctx);
Scalar gpu_dot2 = d_a.dot(d_b);
VERIFY(numext::abs(gpu_dot2 - cpu_dot) < tol * numext::abs(cpu_dot) + tol);
GpuContext::setThreadLocal(nullptr);
// Empty vectors: dot and norm must return zero.
{
DeviceMatrix<Scalar> d_empty(0, 1);
DeviceMatrix<Scalar> d_empty2(0, 1);
Scalar empty_dot = d_empty.dot(ctx, d_empty2);
VERIFY_IS_EQUAL(empty_dot, Scalar(0));
RealScalar empty_sqnorm = d_empty.squaredNorm(ctx);
VERIFY_IS_EQUAL(empty_sqnorm, RealScalar(0));
RealScalar empty_norm = d_empty.norm(ctx);
VERIFY_IS_EQUAL(empty_norm, RealScalar(0));
}
}
// ---- cwiseProduct -----------------------------------------------------------
template <typename Scalar>
void test_cwiseProduct() {
using Vec = Matrix<Scalar, Dynamic, 1>;
using RealScalar = typename NumTraits<Scalar>::Real;
const Index n = 256;
Vec a = Vec::Random(n);
Vec b = Vec::Random(n);
Vec ref = a.array() * b.array();
GpuContext ctx;
auto d_a = DeviceMatrix<Scalar>::fromHost(a, ctx.stream());
auto d_b = DeviceMatrix<Scalar>::fromHost(b, ctx.stream());
auto d_c = d_a.cwiseProduct(ctx, d_b);
Vec result = d_c.toHost(ctx.stream());
RealScalar tol = RealScalar(10) * RealScalar(n) * NumTraits<Scalar>::epsilon();
VERIFY((result - ref).norm() < tol * ref.norm() + tol);
}
EIGEN_DECLARE_TEST(gpu_device_matrix) {
CALL_SUBTEST(test_default_construct());
CALL_SUBTEST(test_empty());
@@ -242,4 +454,18 @@ EIGEN_DECLARE_TEST(gpu_device_matrix) {
CALL_SUBTEST(test_scalar<double>());
CALL_SUBTEST(test_scalar<std::complex<float>>());
CALL_SUBTEST(test_scalar<std::complex<double>>());
CALL_SUBTEST(test_blas1<float>(256));
CALL_SUBTEST(test_blas1<double>(256));
CALL_SUBTEST(test_blas1<std::complex<float>>(256));
CALL_SUBTEST(test_blas1<std::complex<double>>(256));
CALL_SUBTEST(test_cg_operators<float>(256));
CALL_SUBTEST(test_cg_operators<double>(256));
CALL_SUBTEST(test_cg_operators<std::complex<float>>(256));
CALL_SUBTEST(test_cg_operators<std::complex<double>>(256));
CALL_SUBTEST(test_device_scalar<float>());
CALL_SUBTEST(test_device_scalar<double>());
CALL_SUBTEST(test_device_scalar<std::complex<float>>());
CALL_SUBTEST(test_device_scalar<std::complex<double>>());
CALL_SUBTEST(test_cwiseProduct<float>());
CALL_SUBTEST(test_cwiseProduct<double>());
}