CTC-Trained LSTM

Closed weights IDSIA,Technical University of Munich 114.7K parameters June 2006

No estimate

No hardware requirements for this model

The weights for this model have not been published, so it cannot be downloaded or run on your own hardware at any size. It is reachable only through its provider, and no graphics card changes that.

On record

Full specification

Everything on record for this model. Most of it describes how it was trained rather than how it runs — useful context for judging how much work went into it, and how it compares with models built at a different scale.

Origin

Who built this model, where, and when it was published.

Organisation
IDSIA,Technical University of Munich
Organisation type
Academia,Academia
Country
Switzerland, Germany
Published
25 June 2006
Authors
Alex Graves, Santiago Fernández, Faustino Gómez, Jürgen Schmidhuber

What it does

The problem areas the model was built for. A model can carry several of each.

Domain
Speech
Task
Speech recognition (ASR)

Size

How large the model is and how much data it was trained on. Parameters are the figure that decides whether it fits on a given graphics card.

Parameters
114.7K

"The hidden layers were fully connected to themselves and the output layer, and fully connected from the input layer. The input layer was size 26, the softmax output layer size 62 (61 phoneme categories plus the blank label), and the total number of weights was 114, 662." https://www.cs.toronto.edu/~graves/icml_2006.pdf

Training data
tokens

4162 utterances, guesstimated avg 10 words per utterance

How it is classified

Labels the source dataset applies when tracking notable models, and how confident it is in the entry.

Citations
4,862

Sources

Where this record came from and when it was last checked.

Reference
Connectionist Temporal Classification: Labelling Unsegmented Sequence Data with Recurrent Neural Networks
Last updated
28 November 2025

What the numbers mean

Background

CTC-Trained LSTM was published by IDSIA,Technical University of Munich, in Switzerland, in June 2006. The organisation is categorised as academia,Academia.

It works in Speech, and is recorded as doing speech recognition (ASR).

Its weights were never published, so it can only be reached through its provider. No graphics card changes that.

Answers

CTC-Trained LSTM — common questions

01

What GPU do I need to run CTC-Trained LSTM?

None. CTC-Trained LSTM is a closed model — its weights were never published, so it cannot be downloaded or run on your own hardware at any price. It is reachable only through its provider.

02

Is CTC-Trained LSTM open source?

The licensing for CTC-Trained LSTM was never recorded in our source data. We treat unstated licensing as closed, because an unrecorded licence is not one to rely on.

03

How many parameters does CTC-Trained LSTM have?

CTC-Trained LSTM has 114.7K parameters. "The hidden layers were fully connected to themselves and the output layer, and fully connected from the input layer. The input layer was size 26, the softmax output layer size 62 (61 phoneme categories plus the blank label), and the total number of weights was 114, 662." https://www.cs.toronto.edu/~graves/icml_2006.pdf. That figure is the total, and it is what decides how much memory the model needs — roughly half a gigabyte per billion at the compression most people use.

04

Who created CTC-Trained LSTM?

CTC-Trained LSTM was published by IDSIA,Technical University of Munich, based in Switzerland, categorised as academia,Academia.

05

When was CTC-Trained LSTM released?

CTC-Trained LSTM was published in June 2006. Capability per parameter has improved considerably since, so a newer model of the same size is often the better use of the same hardware.

06

What is CTC-Trained LSTM used for?

CTC-Trained LSTM works in Speech, and is recorded as handling speech recognition (ASR). Models frequently carry more than one of each, and the tags describe purpose rather than capability limits.

Source

Original publication

Record last updated 28 November 2025

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