digraph ICAdiagram {

    /* LAYOUT CONTROL */

    rankdir=LR

    newrank=true

    ranksep=0.75

    clusterrank=local

    /* GLOBAL STYLES */

    splines=true

    fontsize=20

    fontname="Source Code Pro"

    node [style="filled"

          fontsize=18

          fontname="Source Sans Pro"]

    edge [arrowsize=1.2

          penwidth=2.5

          color="gray50"

          fontsize=12

          fontname="Source Code Pro"]

    /* starting nodes */

    sensor [label="Sensor data" shape="box" fillcolor="#bbbbbb"]

    cov [label="Noise cov" shape="box" fillcolor="#bbbbbb"]

    /* ICA.FIT() */

    subgraph cluster_0 {

        label="ICA.fit()"

        color="#009988"

        fontcolor="#009988"

        penwidth=1.5

        /* PRE-WHITENING */

        subgraph cluster_1 {

            label="Whitening"

            style="dashed"

            fontname="Source Sans Pro"

            color="gray50"

            fontcolor="gray50"

            /* nodes & edges */

            pre [label="Pre-\nwhiten" fontsize=11 shape="circle" fillcolor="#ee7733"]

            pre -> pca

            pca        [label="PCA"                   shape="circle" fillcolor="#ee7733"]

            pcs        [label="Principal\ncomponents" shape="box"    fillcolor="#33bbee"]

            pca -> pcs

        }

        /* nodes & edges */

        ica        [label="ICA"                     shape="circle" fillcolor="#ee7733"]

        ics        [label="Independent\ncomponents" shape="box"    fillcolor="#33bbee"]

        ica -> ics [label="n_components\r"]

    }

    /* ICA.APPLY() */

    subgraph cluster_2 {

        label="ICA.apply()"

        color="#ee3377"

        fontcolor="#ee3377"

        penwidth=1.5

        /* ending node */

        recon [label="Reconstructed\nsensor data" shape="box" fillcolor="#bbbbbb"]

    }

    /* subgraph-crossing edges */

    sensor -> pre  [label="all sensor channels\r" fontsize=14 fontname="Source Sans Pro"]

    cov -> pre     [label="covariance or std. dev.\r" fontsize=14 fontname="Source Sans Pro"]

    pcs -> ica     [label="n_components\l"]

    ics -> recon   [constraint=false color="#ee3377"

                    xlabel="Retained ICs:\ln_components -\llen(ICA.exclude)\l"]

    pcs -> recon   [constraint=false color="#ee3377"

                    xlabel="PCA residual:\ln_pca_components\l- n_components\l"]

    /* position recon box where we want it */

    { rank="same" recon ica }

}