Mercurial > gemma
view pkg/common/nashsutcliffe.go @ 4606:dfe9cde6a20c geoserver_sql_views
Reflect database model changes for SQL views in backend
In principle, we could use many datasources with different database
schemas, but this would imply changing GeoServer initialization,
service filtering, endpoints and eventually more. Since we do not need
it, just hard-code the schema name as a constant.
author | Tom Gottfried <tom@intevation.de> |
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date | Thu, 05 Sep 2019 12:23:31 +0200 |
parents | 8c5df0f3562e |
children | 6270951dda28 |
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// This is Free Software under GNU Affero General Public License v >= 3.0 // without warranty, see README.md and license for details. // // SPDX-License-Identifier: AGPL-3.0-or-later // License-Filename: LICENSES/AGPL-3.0.txt // // Copyright (C) 2019 by via donau // – Österreichische Wasserstraßen-Gesellschaft mbH // Software engineering by Intevation GmbH // // Author(s): // * Sascha L. Teichmann <sascha.teichmann@intevation.de> package common import ( "fmt" "time" ) type ( // TimedValue is a tuple of a point in time and an associated value. TimedValue struct { When time.Time Value float64 } // TimedValues is a slice of TimedValue tuples. TimedValues []TimedValue ) func epsEquals(a, b time.Time) bool { d := a.Sub(b) return -10*time.Millisecond < d && d < 10*time.Millisecond } // Find scans to the tuples and compares the time with an // epsilon of ten micro seconds. If they are equals the associated // value is returned. The return bool flags indicated if the // search was successful. func (mvs TimedValues) Find(when time.Time) (float64, bool) { for i := range mvs { if epsEquals(when, mvs[i].When) { return mvs[i].Value, true } } return 0, false } // NashSutcliffe calculates the Nash-Sutcliffe coefficent for // given predicted and observed values. // See // https://en.wikipedia.org/wiki/Nash%E2%80%93Sutcliffe_model_efficiency_coefficient // for details. // The function panics if predicted and observed are of different lengths. func NashSutcliffe(predicted, observed []float64) float64 { if len(predicted) != len(observed) { panic(fmt.Sprintf( "NashSutcliffe: predicted and observed len differ: %d != %d", len(predicted), len(observed))) } if len(observed) == 0 { return 0 } var mo float64 for _, v := range observed { mo += v } mo /= float64(len(observed)) var num, denom float64 for i, o := range observed { d1 := predicted[i] - o num += d1 * d1 d2 := o - mo denom += d2 * d2 } return 1 - num/denom }