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filt

filt(b, a, x, [si])

Apply filter described by vectors a and b to vector x, with an optional initial filter state vector si (defaults to zeros).

Examples

1. Filter a vector using coefficients a and b:

   julia> a = [1, -0.5];
   julia> b = [0.25, 0.5];
   julia> x = [1, 2, 3, 4, 5];
   julia> filt(b, a, x)
   5-element Array{Float64,1}:
   0.25
   1.0
   1.625
   2.375
   3.1875

   This example applies the filter described by the coefficient vectors a and b to the input vector x.

2. Apply filter with an initial state vector:

   julia> a = [1, -0.5];
   julia> b = [0.25, 0.5];
   julia> x = [1, 2, 3, 4, 5];
   julia> si = [0.5, 0.75];
   julia> filt(b, a, x, si)
   5-element Array{Float64,1}:
   0.375
   1.4375
   1.96875
   2.984375
   3.9921875

   In this example, an initial filter state vector si is provided, which affects the output of the filter.

Common mistake example:

julia> a = [1, -0.5];
julia> b = [0.25, 0.5];
julia> x = [1, 2, 3, 4, 5];
julia> filt(b, a, x, [0.1, 0.2, 0.3])
ERROR: DimensionMismatch("Cannot multiply two vectors")

In this example, the initial state vector si has a different length than the coefficient vectors a and b. It's important to ensure that the dimensions of the coefficient vectors and the initial state vector match for the filter operation to be valid.

See Also

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