Discrete convolution calculator

Calculate convolved sequence and output length with your own figures.

Your numbers

Use the units shown. Results update as you change valid inputs.

Use convolved sequence and output length to compare changes to your inputs. The method and limits below explain the scope.

Examples

Examples

Try the starting example

First finite real sequence
1,2
Second finite real sequence
3,4
Output mode: full, same or valid
full
Convolved sequence
3, 10, 8
Output length
3
Starting index relative to full convolution
0
Sum of returned sequence
21

Try another scenario

First finite real sequence
1,2
Second finite real sequence
3,4
Output mode: full, same or valid
valid
Convolved sequence
10
Output length
1
Starting index relative to full convolution
1
Sum of returned sequence
10
Calculation method

Calculation method

Convolved sequence

Full y[k]=sum(a[i]×b[k−i]) with zero outside input bounds. Same takes the centred max(input lengths) entries; valid keeps entries with complete overlap.

Output length

Number of returned entries.

Starting index relative to full convolution

Full starts at 0; same at floor((full length−max input length)/2); valid at min input length−1.

Sum of returned sequence

Sum only the selected output entries; truncated modes do not preserve the full-convolution sum identity.

Symbols and units
a
First finite real sequence
b
Second finite real sequence
c
Output mode: full, same or valid

Use the units shown. A list keeps the order in which you enter its values. The symbol ^ means “raised to the power of”.

Calculation steps and notation

sum(list) adds all entries in the list.

Assumptions & limits

Assumptions & limits

  • Linear discrete convolution of two finite real sequences, with combined input length at most 500. This is not circular convolution; full indexing assumes both input first elements have index zero. Double-precision results are approximate. Numeric tables use 12 significant digits and display components at roundoff scale (32 machine epsilons relative to their row or relevant calculation scale) as zero; scalar diagnostics retain full precision.
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These calculations run in your browser. A shared link contains the values you choose to share. Only questions submitted to the separate AI finder are sent to OpenAI.

Further reading

NumPy: linear convolution modes ↗

Background reading; this does not imply endorsement or independent review of SumFizz.

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