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Doc: difference between array and matrix cosine etc (bug #830)

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This commit is contained in:
Jitse Niesen 2014-09-06 14:59:44 +01:00
parent 25bceefb4e
commit abb33258ce
2 changed files with 35 additions and 4 deletions
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18
Eigen/src/plugins/ArrayCwiseUnaryOps.h
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@ -29,6 +29,9 @@ abs2() const
}
/** \returns an expression of the coefficient-wise exponential of *this.
*
* This function computes the coefficient-wise exponential. The function MatrixBase::exp() in the
* unsupported module MatrixFunctions computes the matrix exponential.
*
* Example: \include Cwise_exp.cpp
* Output: \verbinclude Cwise_exp.out
@ -43,6 +46,9 @@ exp() const
}
/** \returns an expression of the coefficient-wise logarithm of *this.
*
* This function computes the coefficient-wise logarithm. The function MatrixBase::log() in the
* unsupported module MatrixFunctions computes the matrix logarithm.
*
* Example: \include Cwise_log.cpp
* Output: \verbinclude Cwise_log.out
@ -57,6 +63,9 @@ log() const
}
/** \returns an expression of the coefficient-wise square root of *this.
*
* This function computes the coefficient-wise square root. The function MatrixBase::sqrt() in the
* unsupported module MatrixFunctions computes the matrix square root.
*
* Example: \include Cwise_sqrt.cpp
* Output: \verbinclude Cwise_sqrt.out
@ -71,6 +80,9 @@ sqrt() const
}
/** \returns an expression of the coefficient-wise cosine of *this.
*
* This function computes the coefficient-wise cosine. The function MatrixBase::cos() in the
* unsupported module MatrixFunctions computes the matrix cosine.
*
* Example: \include Cwise_cos.cpp
* Output: \verbinclude Cwise_cos.out
@ -86,6 +98,9 @@ cos() const
/** \returns an expression of the coefficient-wise sine of *this.
*
* This function computes the coefficient-wise sine. The function MatrixBase::sin() in the
* unsupported module MatrixFunctions computes the matrix sine.
*
* Example: \include Cwise_sin.cpp
* Output: \verbinclude Cwise_sin.out
@ -155,6 +170,9 @@ atan() const
}
/** \returns an expression of the coefficient-wise power of *this to the given exponent.
*
* This function computes the coefficient-wise power. The function MatrixBase::pow() in the
* unsupported module MatrixFunctions computes the matrix power.
*
* Example: \include Cwise_pow.cpp
* Output: \verbinclude Cwise_pow.out

21
unsupported/Eigen/MatrixFunctions
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@ -82,7 +82,9 @@ const MatrixFunctionReturnValue<Derived> MatrixBase<Derived>::cos() const
\param[in] M a square matrix.
\returns expression representing \f$ \cos(M) \f$.
This function calls \ref matrixbase_matrixfunction "matrixFunction()" with StdStemFunctions::cos().
This function computes the matrix cosine. Use ArrayBase::cos() for computing the entry-wise cosine.
The implementation calls \ref matrixbase_matrixfunction "matrixFunction()" with StdStemFunctions::cos().
\sa \ref matrixbase_sin "sin()" for an example.
@ -123,6 +125,9 @@ differential equations: the solution of \f$ y' = My \f$ with the
initial condition \f$ y(0) = y_0 \f$ is given by
\f$ y(t) = \exp(M) y_0 \f$.
The matrix exponential is different from applying the exp function to all the entries in the matrix.
Use ArrayBase::exp() if you want to do the latter.
The cost of the computation is approximately \f$ 20 n^3 \f$ for
matrices of size \f$ n \f$. The number 20 depends weakly on the
norm of the matrix.
@ -177,6 +182,9 @@ the scalar logarithm, the equation \f$ \exp(X) = M \f$ may have
multiple solutions; this function returns a matrix whose eigenvalues
have imaginary part in the interval \f$ (-\pi,\pi] \f$.
The matrix logarithm is different from applying the log function to all the entries in the matrix.
Use ArrayBase::log() if you want to do the latter.
In the real case, the matrix \f$ M \f$ should be invertible and
it should have no eigenvalues which are real and negative (pairs of
complex conjugate eigenvalues are allowed). In the complex case, it
@ -232,7 +240,8 @@ const MatrixPowerReturnValue<Derived> MatrixBase<Derived>::pow(RealScalar p) con
The matrix power \f$ M^p \f$ is defined as \f$ \exp(p \log(M)) \f$,
where exp denotes the matrix exponential, and log denotes the matrix
logarithm.
logarithm. This is different from raising all the entries in the matrix
to the p-th power. Use ArrayBase::pow() if you want to do the latter.
If \p p is complex, the scalar type of \p M should be the type of \p
p . \f$ M^p \f$ simply evaluates into \f$ \exp(p \log(M)) \f$.
@ -391,7 +400,9 @@ const MatrixFunctionReturnValue<Derived> MatrixBase<Derived>::sin() const
\param[in] M a square matrix.
\returns expression representing \f$ \sin(M) \f$.
This function calls \ref matrixbase_matrixfunction "matrixFunction()" with StdStemFunctions::sin().
This function computes the matrix sine. Use ArrayBase::sin() for computing the entry-wise sine.
The implementation calls \ref matrixbase_matrixfunction "matrixFunction()" with StdStemFunctions::sin().
Example: \include MatrixSine.cpp
Output: \verbinclude MatrixSine.out
@ -428,7 +439,9 @@ const MatrixSquareRootReturnValue<Derived> MatrixBase<Derived>::sqrt() const
The matrix square root of \f$ M \f$ is the matrix \f$ M^{1/2} \f$
whose square is the original matrix; so if \f$ S = M^{1/2} \f$ then
\f$ S^2 = M \f$.
\f$ S^2 = M \f$. This is different from taking the square root of all
the entries in the matrix; use ArrayBase::sqrt() if you want to do the
latter.
In the <b>real case</b>, the matrix \f$ M \f$ should be invertible and
it should have no eigenvalues which are real and negative (pairs of