diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..0a95508
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+.idea/
+.vscode/
\ No newline at end of file
diff --git a/stubs/Colvec.php b/stubs/Colvec.php
new file mode 100644
index 0000000..780ee7e
--- /dev/null
+++ b/stubs/Colvec.php
@@ -0,0 +1,8 @@
+<?php
+
+namespace Arma;
+
+interface Colvec
+{
+
+}
\ No newline at end of file
diff --git a/stubs/CxMat.php b/stubs/CxMat.php
new file mode 100644
index 0000000..5bb826d
--- /dev/null
+++ b/stubs/CxMat.php
@@ -0,0 +1,20 @@
+<?php
+
+namespace Arma;
+
+/**
+ * Interface for a dense matrix with complex numbers as elements.
+ *
+ * @package Arma
+ */
+interface CxMat extends Mat
+{
+    /**
+     * Construct a complex matrix out of two non-complex matrices.
+     *
+     * @param Mat $real
+     * @param Mat $imag
+     * @return CxMat
+     */
+    static function fromMats($real, $imag);
+}
diff --git a/stubs/Fill.php b/stubs/Fill.php
new file mode 100644
index 0000000..cbeddfc
--- /dev/null
+++ b/stubs/Fill.php
@@ -0,0 +1,36 @@
+<?php
+
+namespace Arma;
+
+abstract class Fill
+{
+    /**
+     * Do not modify the elements.
+     */
+    const NONE = 0;
+
+    /**
+     * Set all elements to 0.
+     */
+    const ZEROS = 1;
+
+    /**
+     * Set all elements to 1.
+     */
+    const ONES = 2;
+
+    /**
+     * Set the elements along the main diagonal to 1 and off-diagonal elements to 0.
+     */
+    const EYE = 3;
+
+    /**
+     * Set each element to a random value from a uniform distribution in the [0,1] interval.
+     */
+    const RANDU = 4;
+
+    /**
+     * Set each element to a random value from a normal/Gaussian distribution with zero mean and unit variance.
+     */
+    const RANDN = 5;
+}
\ No newline at end of file
diff --git a/stubs/Mat.php b/stubs/Mat.php
new file mode 100644
index 0000000..cddb7b6
--- /dev/null
+++ b/stubs/Mat.php
@@ -0,0 +1,46 @@
+<?php
+
+namespace Arma;
+
+/**
+ * Interface for a dense matrix.
+ *
+ * @package Arma
+ */
+interface Mat
+{
+    /**
+     * Construct the matrix to have user specified dimensions and fill with specified pattern.
+     *
+     * @param int $in_rows
+     * @param int $in_cols
+     * @param int $fill[optional]
+     * @return Mat
+     */
+    static function init($in_rows, $in_cols, $fill);
+
+    /**
+     * Create the matrix from a textual description.
+     *
+     * @param string $text
+     * @return Mat
+     */
+    static function fromString($text);
+
+    /**
+     * Create the matrix from a column or row vector.
+     *
+     * @param Colvec|Rowvec $vector
+     * @return Mat
+     */
+    static function fromVec($vector);
+
+    /**
+     * Create the matrix from a sparse matrix.
+     *
+     * @param SpMat $sp_mat
+     * @return Mat
+     */
+    static function fromSparse($sp_mat);
+
+}
\ No newline at end of file
diff --git a/stubs/Rowvec.php b/stubs/Rowvec.php
new file mode 100644
index 0000000..3669a41
--- /dev/null
+++ b/stubs/Rowvec.php
@@ -0,0 +1,8 @@
+<?php
+
+namespace Arma;
+
+interface Rowvec
+{
+
+}
\ No newline at end of file
diff --git a/stubs/SpMat.php b/stubs/SpMat.php
new file mode 100644
index 0000000..03ace26
--- /dev/null
+++ b/stubs/SpMat.php
@@ -0,0 +1,8 @@
+<?php
+
+namespace Arma;
+
+interface SpMat
+{
+
+}
\ No newline at end of file
diff --git a/stubs/Vec.php b/stubs/Vec.php
new file mode 100644
index 0000000..0ef7fd2
--- /dev/null
+++ b/stubs/Vec.php
@@ -0,0 +1,5 @@
+<?php
+
+namespace arma;
+
+class_alias(Colvec::class, 'arma\\Vec');
diff --git a/stubs/a.php b/stubs/a.php
new file mode 100644
index 0000000..a4abe2d
--- /dev/null
+++ b/stubs/a.php
@@ -0,0 +1,2 @@
+<?php
+
diff --git a/stubs/impl/CxDmat.php b/stubs/impl/CxDmat.php
new file mode 100644
index 0000000..4247f86
--- /dev/null
+++ b/stubs/impl/CxDmat.php
@@ -0,0 +1,36 @@
+<?php
+
+namespace Arma;
+
+class CxDmat implements CxMat
+{
+    /**
+     * @inheritdoc
+     * @return CxDmat
+     */
+    static function init($in_rows, $in_cols, $fill = null) {}
+
+    /**
+     * @inheritdoc
+     * @return CxDmat
+     */
+    public static function fromMats($real, $imag) {}
+
+    /**
+     * @inheritdoc
+     * @return CxDmat
+     */
+    static function fromSparse($sp_mat) {}
+
+    /**
+     * @inheritdoc
+     * @return CxDmat
+     */
+    static function fromString($text) {}
+
+    /**
+     * @inheritdoc
+     * @return CxDmat
+     */
+    static function fromVec($vector) {}
+}
diff --git a/stubs/impl/CxImat.php b/stubs/impl/CxImat.php
new file mode 100644
index 0000000..f314eba
--- /dev/null
+++ b/stubs/impl/CxImat.php
@@ -0,0 +1,36 @@
+<?php
+
+namespace Arma;
+
+class CxImat implements CxMat
+{
+    /**
+     * @inheritdoc
+     * @return CxImat
+     */
+    static function init($in_rows, $in_cols, $fill = 0) {}
+
+    /**
+     * @inheritdoc
+     * @return CxImat
+     */
+    public static function fromMats($real, $imag) {}
+
+    /**
+     * @inheritdoc
+     * @return CxImat
+     */
+    static function fromSparse($sp_mat) {}
+
+    /**
+     * @inheritdoc
+     * @return CxImat
+     */
+    static function fromString($text) {}
+
+    /**
+     * @inheritdoc
+     * @return CxImat
+     */
+    static function fromVec($vector) {}
+}
diff --git a/stubs/impl/Dmat.php b/stubs/impl/Dmat.php
new file mode 100644
index 0000000..c29befd
--- /dev/null
+++ b/stubs/impl/Dmat.php
@@ -0,0 +1,30 @@
+<?php
+
+namespace Arma;
+
+class Dmat implements Mat
+{
+    /**
+     * @inheritdoc
+     * @return Dmat
+     */
+    static function init($in_rows, $in_cols, $fill = null) {}
+
+    /**
+     * @inheritdoc
+     * @return Dmat
+     */
+    static function fromSparse($sp_mat) {}
+
+    /**
+     * @inheritdoc
+     * @return Dmat
+     */
+    static function fromString($text) {}
+
+    /**
+     * @inheritdoc
+     * @return Dmat
+     */
+    static function fromVec($vector) {}
+}
diff --git a/stubs/impl/Imat.php b/stubs/impl/Imat.php
new file mode 100644
index 0000000..296aa12
--- /dev/null
+++ b/stubs/impl/Imat.php
@@ -0,0 +1,30 @@
+<?php
+
+namespace Arma;
+
+class Imat implements Mat
+{
+    /**
+     * @inheritdoc
+     * @return Imat
+     */
+    static function init($in_rows, $in_cols, $fill = 0) {}
+
+    /**
+     * @inheritdoc
+     * @return Imat
+     */
+    static function fromSparse($sp_mat) {}
+
+    /**
+     * @inheritdoc
+     * @return Imat
+     */
+    static function fromString($text) {}
+
+    /**
+     * @inheritdoc
+     * @return Imat
+     */
+    static function fromVec($vector) {}
+}