### Question:
FloatMatrix { public float dot(FloatMatrix other) { return blas_sdot(other); } FloatMatrix();  FloatMatrix(float[] data, int numRows, int numCols);  FloatMatrix(float[] data, int numRows, int numCols, boolean copy);  FloatMatrix(float[][] gridData); void assume(float[] data, int numRows, int numCols); static FloatMatrix zeroes(int numRows, int numCols); static FloatMatrix ones(int numRows, int numCols); static FloatMatrix eye(int size); static FloatMatrix columnVector(float[] data); static FloatMatrix columnVector(float[] data, boolean copy); static FloatMatrix rowVector(float[] data); static FloatMatrix rowVector(float[] data, boolean copy); FloatMatrix copy(); float[][] asGrid(); float[] asColumnArray(); float[] asRowArray(); float get(int row, int col); void set(int row, int col, float value); int size(); int numRows(); int numCols(); @Override boolean equals(Object otherObj); @Override String toString(); FloatMatrix elementSub(FloatMatrix other); FloatMatrix elementSub(FloatMatrix other, boolean inPlace); FloatMatrix elementAdd(FloatMatrix other); FloatMatrix elementAdd(FloatMatrix other, boolean inPlace); FloatMatrix elementMul(FloatMatrix other); FloatMatrix elementMul(FloatMatrix other, boolean inPlace); FloatMatrix elementDiv(FloatMatrix other); FloatMatrix elementDiv(FloatMatrix other, boolean inPlace); FloatMatrix elementLog(); FloatMatrix elementLog(boolean inPlace); FloatMatrix sub(float val); FloatMatrix sub(float val, boolean inPlace); FloatMatrix add(float val); FloatMatrix add(float val, boolean inPlace); FloatMatrix mul(float val); FloatMatrix mul(float val, boolean inPlace); FloatMatrix div(float val); FloatMatrix div(float val, boolean inPlace); float norm1(); float norm2(); FloatMatrix transpose(); FloatMatrix mul(FloatMatrix b); FloatMatrix mul(FloatMatrix b, boolean transposeA, boolean transposeB, float alpha); FloatMatrix mul(FloatMatrix b, FloatMatrix c, boolean transposeA, boolean transposeB, float alpha, float beta); float dot(FloatMatrix other); FloatMatrix inverse(); FloatMatrix choleskyDecomposition(); FloatMatrix choleskyDecomposition(boolean inPlace); int[] lapack_sgesv(FloatMatrix b); void lapack_spotrf(boolean upper); FloatMatrix blas_sgemm(
            FloatMatrix b, FloatMatrix c,
            boolean transposeA, boolean transposeB,
            float alpha, float beta); float blas_sdot(FloatMatrix y);  }### Answer:
@Test public void testDot() { FloatMatrix x; FloatMatrix y; x = FloatMatrix.columnVector(new float[]{1.0f, 2.0f, 3.0f}); y = FloatMatrix.columnVector(new float[]{4.0f, 5.0f, 6.0f}); assertEquals(32.0f, x.dot(y), EPSILON); assertEquals(32.0f, y.dot(x), EPSILON); try { x = new FloatMatrix(new float[][]{{1.0f, 2.0f}, {3.0f, 4.0f}}); y = new FloatMatrix(new float[][]{{1.0f, 2.0f}, {3.0f, 4.0f}}); x.dot(y); fail("Failed to throw exception on non-vector dot."); } catch (IllegalArgumentException ex) { } try { x = FloatMatrix.columnVector(new float[]{1.0f, 2.0f, 3.0f}); y = FloatMatrix.columnVector(new float[]{4.0f, 5.0f}); x.dot(y); fail("Failed to throw exception on mismatched-size dot."); } catch (IllegalArgumentException ex) { } }