# Matrix

### extracellular matrix   (細胞外マトリックス)

An extracellular matrix (ECM) is also present in metazoans.

The extracellular matrix (ECM) of collagen is what gives it its high strength.

These scaffolds fulfill a similar purpose as the extracellular matrix in natural tissue.

### covariance matrix   (共分散行列)

The covariance matrix encodes the mutual variance of several random variables.

Each axis on a PCA plot is an eigenvector of the covariance matrix of shape variables.

If the number of clusters is low the estimated covariance matrix can be downward biased.

### identity matrix   (単位行列)

Finally, , where "I" is the identity matrix.

If is a positive integer, then denotes the identity matrix.

The formula defines a translation if and only if "A" is the identity matrix.

### matrix multiplication (行列の乗算)

The ket can be computed by normal matrix multiplication.

Code for matrix multiplication hardware design verification:

Then the bra can be computed by normal matrix multiplication.

### square matrix   (正方行列)

The matrix is augmented to create a 4x4 square matrix.

The entries "a" form the main diagonal of a square matrix.

Then: Assume in addition that is a square matrix of size .

### density matrix

in such a basis the density matrix is diagonal.

However, one can again find the time evolution of the density matrix formula_13 rsp.

Mathematically, for a given density matrix formula_13, the von Neumann entropy formula_12 is formula_15.

### diagonal matrix   (対角行列)

If all entries outside the main diagonal are zero, A is called a diagonal matrix.

(It is represented in any coordinate system by a 3 × 3 diagonal matrix with equal values along the diagonal.)

Singular value decomposition expresses any matrix A as a product UDV, where U and V are unitary matrices and D is a diagonal matrix.

### dot matrix   (ドットマトリックス)

The dot matrix printer was subsequently replaced by laser printers.

The benches have computer-generated dot matrix patterns sandblasted into the seats.

Some dot matrix printers, such as the NEC P6300, can be upgraded to print in colour.

### rotation matrix

It is an affine transform consisting of the 3x3 rotation matrix "R" and the 1x3 translation vector "p".

For example, the rotation matrix in 2d: is a matrix valued function of rotation angle of about the origin.

Let the displacement of a body be defined by "D" = (["A"], d), where ["A"] is the rotation matrix and d is the translation vector.