Package Scientific :: Package Functions :: Module Interpolation :: Class InterpolatingFunction

Class InterpolatingFunction

Known Subclasses:

Function defined by values on a grid using interpolation

An interpolating function of n variables with m-dimensional values is defined by an (n+m)-dimensional array of values and n one-dimensional arrays that define the variables values corresponding to the grid points. The grid does not have to be equidistant.

An InterpolatingFunction object has attributes real and imag like a complex function (even if its values are real).

Instance Methods

__abs__(self)

number

__call__(self, *points)
Returns: the function value obtained by linear interpolation

__getattr__(self, attr)

InterpolatingFunction or number

__getitem__(self, i)
Returns: an InterpolatingFunction whose number of variables is reduced, or a number if no variable is left

InterpolatingFunction or number

__getslice__(self, i, j)
Returns: an InterpolatingFunction whose number of variables is reduced by one, or a number if no variable is left

__init__(self, axes, values, default=None, period=None)

int

__len__(self)
Returns: number of variables

arccos(self)

arcsin(self)

arctan(self)

cos(self)

cosh(self)

InterpolatingFunction or number

definiteIntegral(self, variable=0)
Returns: a new InterpolatingFunction containing the numerical integral.

InterpolatingFunction

derivative(self, variable=0)
Returns: a new InterpolatingFunction containing the numerical derivative

exp(self)

Scientific.Functions.Polynomial

fitPolynomial(self, order)
Returns: a polynomial whose coefficients have been obtained by a least-squares fit to the grid values

InterpolatingFunction

integral(self, variable=0)
Returns: a new InterpolatingFunction containing the numerical integral.

log(self)

InterpolatingFunction

selectInterval(self, first, last, variable=0)
Returns: a new InterpolatingFunction whose grid is restricted

sin(self)

sinh(self)

sqrt(self)

tan(self)

tanh(self)

Method Details

call(self, points)
(Call operator)*

Returns: number

the function value obtained by linear interpolation

Raises:

TypeError - if the number of arguments (len(points)) does not match the number of variables of the function
ValueError - if the evaluation point is outside of the domain of definition and no default value is defined

getitem(self, i)
(Indexing operator)

Parameters:

i (indexing expression) - any indexing expression possible for N.array that does not use N.NewAxis

Returns: InterpolatingFunction or number

an InterpolatingFunction whose number of variables is reduced, or a number if no variable is left

Raises:

TypeError - if i is not an allowed index expression

getslice(self, i, j)
(Slicling operator)

Parameters:

i (int) - lower slice index
j (int) - upper slice index

Returns: InterpolatingFunction or number

an InterpolatingFunction whose number of variables is reduced by one, or a number if no variable is left

init(self, axes, values, default=None, period=None)
(Constructor)

Parameters:

axes (sequence of N.array) - a sequence of one-dimensional arrays, one for each variable, specifying the values of the variables at the grid points
values (N.array) - the function values on the grid
default (number or None) - the value of the function outside the grid. A value of None means that the function is undefined outside the grid and that any attempt to evaluate it there raises an exception.
period (sequence of numbers or None) - the period for each of the variables, or None for variables in which the function is not periodic.

len(self)
(Length operator)

Returns: int: number of variables

definiteIntegral(self, variable=0)

Parameters:

variable (int) - the index of the variable of the function with respect to which the integration is performed

Returns: InterpolatingFunction or number

a new InterpolatingFunction containing the numerical integral. The integration constant is defined such that the integral at the first grid point is zero. If the original function has only one free variable, the definite integral is a number

derivative(self, variable=0)

Parameters:

variable (int) - the index of the variable of the function with respect to which the derivative is taken

Returns: InterpolatingFunction

a new InterpolatingFunction containing the numerical derivative

fitPolynomial(self, order)

Parameters:

order (int) - the order of the polynomial to be fitted

Returns: Scientific.Functions.Polynomial

a polynomial whose coefficients have been obtained by a least-squares fit to the grid values

integral(self, variable=0)

Parameters:

variable (int) - the index of the variable of the function with respect to which the integration is performed

Returns: InterpolatingFunction

a new InterpolatingFunction containing the numerical integral. The integration constant is defined such that the integral at the first grid point is zero.

selectInterval(self, first, last, variable=0)

Parameters:

first (float) - lower limit of an axis interval
last (float) - upper limit of an axis interval
variable (int) - the index of the variable of the function along which the interval restriction is applied

Returns: InterpolatingFunction

a new InterpolatingFunction whose grid is restricted

Class InterpolatingFunction

__call__(self, *points) (Call operator)

__getitem__(self, i) (Indexing operator)

__getslice__(self, i, j) (Slicling operator)

__init__(self, axes, values, default=None, period=None) (Constructor)

__len__(self) (Length operator)

definiteIntegral(self, variable=0)

derivative(self, variable=0)

fitPolynomial(self, order)

integral(self, variable=0)

selectInterval(self, first, last, variable=0)

call(self, points)
(Call operator)*

getitem(self, i)
(Indexing operator)

getslice(self, i, j)
(Slicling operator)

init(self, axes, values, default=None, period=None)
(Constructor)

len(self)
(Length operator)