# Interface IBasis

All Known Implementing Classes:
`FourierGridBasis`, `GaussiansBasis`, `SimpleBasisSet`

public interface IBasis
A basis set must implement this class.
Author:
Stephan Michels <stephan@vern.chem.tu-berlin.de>
Source code:
main
Belongs to CDK module:
qm
Created on:
2001-07-02
• ## Method Summary

Modifier and Type
Method
Description
`double`
```calcI(int i, int j, int k, int l)```
Calculates a two eletron fout center integral I = <chi_i chi_j | 1/r12 | chi_k chi_l >.
`double`
```calcJ(int i, int j)```
Calculates the impulse J = -<d/dr chi_i | d/dr chi_j>.
`double`
```calcS(int i, int j)```
Calculate the overlap integral S = <phi_i|phi_j>.
`double`
```calcV(int i, int j)```
Calculates the potential V = <chi_i | 1/r | chi_j>.
`double`
`getMaxX()`
Gets the dimension of the volume, which describes the base.
`double`
`getMaxY()`
Gets the dimension of the volume, which describes the base.
`double`
`getMaxZ()`
Gets the dimension of the volume, which describes the base.
`double`
`getMinX()`
Gets the dimension of the volume, which describes the base.
`double`
`getMinY()`
Gets the dimension of the volume, which describes the base.
`double`
`getMinZ()`
Gets the dimension of the volume, which describes the base.
`int`
`getSize()`
Gets the number of base vectors
`double`
```getValue(int index, double x, double y, double z)```
Calculates the function value an (x,y,z).
`Vector`
```getValues(int index, Matrix x)```
Calculates the function values.
• ## Method Details

• ### getSize

int getSize()
Gets the number of base vectors
• ### getMinX

double getMinX()
Gets the dimension of the volume, which describes the base.
• ### getMaxX

double getMaxX()
Gets the dimension of the volume, which describes the base.
• ### getMinY

double getMinY()
Gets the dimension of the volume, which describes the base.
• ### getMaxY

double getMaxY()
Gets the dimension of the volume, which describes the base.
• ### getMinZ

double getMinZ()
Gets the dimension of the volume, which describes the base.
• ### getMaxZ

double getMaxZ()
Gets the dimension of the volume, which describes the base.
• ### getValue

double getValue(int index, double x, double y, double z)
Calculates the function value an (x,y,z).
Parameters:
`index` - The number of the base
• ### getValues

Vector getValues(int index, Matrix x)
Calculates the function values.
Parameters:
`index` - The number of the base
• ### calcS

double calcS(int i, int j)
Calculate the overlap integral S = <phi_i|phi_j>.
Parameters:
`i` - Index of the first base
`j` - Index of the second base
• ### calcJ

double calcJ(int i, int j)
Calculates the impulse J = -<d/dr chi_i | d/dr chi_j>.
Parameters:
`i` - Index of the first base
`j` - Index of the second base
• ### calcV

double calcV(int i, int j)
Calculates the potential V = <chi_i | 1/r | chi_j>.
Parameters:
`i` - Index of the first base
`j` - Index of the second base
• ### calcI

double calcI(int i, int j, int k, int l)
Calculates a two eletron fout center integral I = <chi_i chi_j | 1/r12 | chi_k chi_l >.
Parameters:
`i` - Index of the first base
`j` - Index of the second base
`k` - Index of the third base
`l` - Index of the fourth base