add spectra (#4013)

* add spectra

* Update xmake.lua

---------

Co-authored-by: star9029 <hengxings783@gmail.com>

packages/s/spectra/xmake.lua

@@ -0,0 +1,30 @@
+package("spectra")
+
+    set_kind("library", {headeronly = true})
+    set_homepage("https://spectralib.org/")
+    set_description("Sparse Eigenvalue Computation Toolkit as a Redesigned ARPACK")
+    set_license("MPL-2.0")
+
+    add_urls("https://github.com/yixuan/spectra/archive/refs/tags/$(version).tar.gz",
+             "https://github.com/yixuan/spectra.git")
+    add_versions("v1.0.1", "919e3fbc8c539a321fd5a0766966922b7637cc52eb50a969241a997c733789f3")
+
+    add_deps("cmake", "eigen")
+    on_install("windows", "macosx", "linux", "mingw", "cross", function (package)
+        import("package.tools.cmake").install(package)
+    end)
+
+    on_test(function (package)
+        assert(package:check_cxxsnippets({test = [[
+            #include <Eigen/Core>
+            #include <Spectra/SymEigsSolver.h>
+            void test() {
+                Eigen::MatrixXd A = Eigen::MatrixXd::Random(10, 10);
+                Eigen::MatrixXd M = A + A.transpose();
+                Spectra::DenseSymMatProd<double> op(M);
+                Spectra::SymEigsSolver<Spectra::DenseSymMatProd<double>> eigs(op, 3, 6);
+                eigs.init();
+                int nconv = eigs.compute(Spectra::SortRule::LargestAlge);
+            }
+        ]]}, {configs = {languages = "c++14"}}))
+    end)