# ifft~

Inverse fast Fourier transform

## Description

ifft~ performs an Inverse FFT (inverse fast Fourier transform) on an input signal.

## Examples

## Arguments

### IFFT-points [int]

The first argument specifies the number of points (samples) in the IFFT. It must be a power of two. The default number of points is 512. The second argument specifies the number of samples between successive IFFTs. This must be at least the number of points, and must be also be a power of two. The default interval is 512. The third argument specifies the offset into the interval where the IFFT will start. This must either be 0 or a multiple of the signal vector size. ifft~ will correct bad arguments, but if you change the signal vector size after creating an ifft~ and the offset is no longer a multiple of the vector size, the ifft~ will not operate when signal processing is turned on.

## Attributes

### Common Box Attributes

### annotation [symbol]

Sets the text that will be displayed in the Clue window when the user moves the mouse over the object.

### background [int] (default: 0)

Adds or removes the object from the patcher's background layer. background 1 adds the object to the background layer, background 0 removes it. Objects in the background layer are shown behind all objects in the default foreground layer.

### color [4 floats]

Sets the color for the object box outline.

### fontface [int]

Sets the type style used by the object. The options are:

plain

bold

italic

bold italic

Possible values:

0 = 'regular'

1 = 'bold'

2 = 'italic'

3 = 'bold italic'

### fontname [symbol]

Sets the object's font.

### fontsize [float]

Sets the object's font size (in points).

Possible values:

'8'

'9'

'10'

'11'

'12'

'13'

'14'

'16'

'18'

'20'

'24'

'30'

'36'

'48'

'64'

'72'

### hidden [int] (default: 0)

Toggles whether an object is hidden when the patcher is locked.

### hint [symbol]

Sets the text that will be displayed in as a pop-up hint when the user moves the mouse over the object in a locked patcher.

### ignoreclick [int] (default: 0)

Toggles whether an object ignores mouse clicks in a locked patcher.

### patching_rect [4 floats] (default: 0. 0. 100. 0.)

Sets the position and size of the object in the patcher window.

### position [2 floats]

Sets the object's x and y position in both patching and presentation modes (if the object belongs to its patcher's presentation), leaving its size unchanged.

### presentation [int] (default: 0)

Sets whether an object belongs to the patcher's presentation.

### presentation_rect [4 floats] (default: 0. 0. 0. 0.)

Sets the x and y position and width and height of the object in the patcher's presentation, leaving its patching position unchanged.

### rect [4 floats]

Sets the x and y position and width and height of the object in both patching and presentation modes (if the object belongs to its patcher's presentation).

### size [2 floats]

Sets the object's width and height in both patching and presentation modes (if the object belongs to its patcher's presentation), leaving its position unchanged.

### textcolor [float]

Sets the color for the object's text in RGBA format.

### textjustification [int]

Text Justification

Possible values:

0 = 'left'

1 = 'center'

2 = 'right'

### varname [symbol]

Sets the patcher's scripting name, which can be used to address the object by name in pattr, scripting messages to thispatcher, and the js object.

## Messages

### phase

#### Arguments

### signal

In right inlet: The imaginary part of a complex signal that will be inverse transformed.

If signals are connected only to the left inlet and left outlet, a real IFFT (inverse Fast Fourier transform) will be performed. Otherwise, a complex IFFT will be performed.

## Output

### signal

Out left outlet: The real part of the inverse Fourier transform of the input. The output begins after all the points of the input have been received.

Out middle outlet: The imaginary part of the inverse Fourier transform of the input. The output begins after all the points of the input have been received.

Out right outlet: A sync signal that ramps from 0 to the number of points minus 1 over the period in which the IFFT output occurs. When the IFFT is not being output (in the case where the interval is larger than the number of points), the sync signal is 0.

## See Also

Name | Description |
---|---|

cartopol | Convert cartesian to polar coordinates |

cartopol~ | Signal Cartesian to Polar coordinate conversion |

fft~ | Fast Fourier transform |

fftin~ | Input for a patcher loaded by pfft~ |

fftinfo~ | Report information about a patcher loaded by pfft~ |

fftout~ | Output for a patcher loaded by pfft~ |

frameaccum~ | Compute "running phase" of successive phase deviation frames |

framedelta~ | Compute phase deviation between successive FFT frames |

pfft~ | Spectral processing manager for patchers |

poltocar | Convert polar to cartesian coordinates |

poltocar~ | Signal Polar to Cartesian coordinate conversion |

vectral~ | Vector-based envelope follower |

MSP Analysis Tutorial 3: Using the FFT | MSP Analysis Tutorial 3: Using the FFT |