Traceback (most recent call last):
  File "<input>", line 1, in <module>
TypeError: arguments did not match any overloaded call:
  QgsIDWInterpolator(list-of-QgsInterpolator.LayerData): argument 1 has unexpected type     'list'
  QgsIDWInterpolator(QgsIDWInterpolator): argument 1 has unexpected type 'list'

import qgis.core
import qgis.analysis

layer = qgis.utils.iface.activeLayer()

layer_data = QgsInterpolator.LayerData()
layer_data.vectorLayer = layer
layer_data.zCoordInterpolation=False
layer_data.InterpolationAttribute =0
layer_data.mInputType = 1

tin_interpolator = QgsTINInterpolator([layer_data])

export_path ="C:/SomeFolder/output.asc"
rect = layer.extent()
res = 10
ncol = int( ( rect.xMaximum() - rect.xMinimum() ) / res )
nrows = int( (rect.yMaximum() - rect.yMinimum() ) / res)

output = QgsGridFileWriter(tin_interpolator,export_path,rect,ncol, nrows,res,res)
output.writeFile(True)

iface.addRasterLayer(export_path, "interpolation_output")

import qgis.analysis
import qgis.core

layer = qgis.utils.iface.activeLayer()
layer_data = QgsInterpolator.LayerData()
layer_data.vectorLayer = layer
layer_data.zCoordInterpolation=False
layer_data.InterpolationAttribute =0
layer_data.mInputType = 1


tin_interpolator = QgsTINInterpolator([layer_data])

export_path = "E:/GIS_Workbench/script_output/test.asc"

rect = layer.extent()
res = 10
ncol = int( ( rect.xMaximum() - rect.xMinimum() ) / res )
nrows = int( (rect.yMaximum() - rect.yMinimum() ) / res)
output = QgsGridFileWriter(tin_interpolator,export_path,rect,ncol,nrows,res,res)
output.writeFile(True)