Delay fit evaluation button

[ckoerber]

On some occasions, if the fit takes very long, users might want to change several parameters before initiating a new fit.

Also, probably rather relevant for meta-configs, some combinations for meta parameters might not be valid (for example x_min > x_max).

To counter running fits in such scenarios @walkloud suggest to include a "stop fit" switch which, when enabled, delays until disabled again.

[ckoerber]

https://community.plotly.com/t/is-there-a-way-to-only-update-on-a-button-press-for-apps-where-updates-are-slow/4679/6

Seems relevant:

import dash
from dash.dependencies import Input, Output, State
import dash_html_components as html
import dash_core_components as dcc

app = dash.Dash()

app.layout = html.Div([
    html.Button('Click Me', id='button'),
    html.H3(id='button-clicks'),

    html.Hr(),

    html.Label('Input 1'),
    dcc.Input(id='input-1'),

    html.Label('Input 2'),
    dcc.Input(id='input-2'),

    html.Label('Slider 1'),
    dcc.Slider(id='slider-1'),

    html.Button(id='button-2'),

    html.Div(id='output')
])

@app.callback(
    Output('button-clicks', 'children'),
    [Input('button', 'n_clicks')])
def clicks(n_clicks):
    return 'Button has been clicked {} times'.format(n_clicks)

@app.callback(
    Output('output', 'children'),
    [Input('button-2', 'n_clicks')],
    state=[State('input-1', 'value'),
     State('input-2', 'value'),
     State('slider-1', 'value')])
def compute(n_clicks, input1, input2, slider1):
    return 'A computation based off of {}, {}, and {}'.format(
        input1, input2, slider1
    )

if __name__ == '__main__':
    app.run_server(debug=True)

I.e., instead of Input to trigger the callback, the second callback uses form values from States.

The thing which makes this relatively hard is that the callback inputs are created when initializing the app, so I would think this needs to be a static configuration option not a dynamic switch.