Exogenous variables offer valuable supplementary information for predicting future endogenous variables. Forecasting with exogenous variables needs to consider both past-to-future dependencies (i.e., temporal correlations) and the influence of exogenous variables on endogenous variables (i.e., channel correlations). This is pivotal when future exogenous variables are available, because they may directly affect the future endogenous variables. Many methods have been proposed for time series forecasting with exogenous variables, focusing on modeling temporal and channel correlations. However, most of them use a two-step strategy, modeling temporal and channel correlations separately, which limits their ability to capture joint correlations across time and channels. Furthermore, in real-world scenarios, time series are frequently affected by various forms of noises, underscoring the critical importance of robustness in such correlations modeling. To address these limitations, we propose GCGNet, a Graph-Consistent Generative Network for time series forecasting with exogenous variables. Specifically, GCGNet first employs a Variational Generator to produce coarse predictions. A Graph Structure Aligner then further guides it by evaluating the consistency between the generated and true correlations, where the correlations are represented as graphs, and are robust to noises. Finally, a Graph Refiner is proposed to refine the predictions to prevent degeneration and improve accuracy. Extensive experiments on 12 real-world datasets demonstrate that GCGNet outperforms state-of-the-art baselines.
Figures & tables
Figure 1: Illustration of forecasting Electricity Demand (i.e., the endogenous variable) with exogenous variable of Air Temperature. Xendo and Yendo are historical and future endogenous variables, and Xexo and Yexo are historical and future exogenous variables.
Figure 3: The architecture of GCGNet. (a) The Variational Generator, which produces coarse prediction. (b) The Graph Structure Aligner, which guides the optimization of the Variational Generator. (c) The Graph VAE, which generates the adjacency matrix for the nodes. (d) The Graph Refiner, which refines the final predictions using the learned adjacency matrix.
Models
GCGNet
TimeXer
TFT
TiDE
DUET
CrossLinear
Amplifier
TimeKAN
xPatch
PatchTST
Metrics
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
NP
24
0.197
0.233
0.236
0.266
0.219
0.249
0.284
0.301
0.246
0.287
0.215
0.261
0.252
0.303
0.273
0.310
0.234
0.278
0.249
0.294
360
0.496
0.442
0.600
0.475
0.539
0.501
0.601
0.498
0.576
0.528
0.593
0.508
0.587
0.534
0.538
0.529
0.523
0.461
0.530
0.498
Avg
0.346
0.337
0.418
0.371
0.379
0.375
0.443
0.400
0.411
0.408
0.404
0.384
0.420
0.418
0.405
0.419
0.378
0.370
0.390
0.396
PJM
24
0.058
0.148
0.075
0.166
0.095
0.195
0.106
0.214
0.072
0.166
0.094
0.197
0.096
0.208
0.115
0.244
0.077
0.168
0.116
0.239
360
0.128
0.223
0.140
0.231
0.133
0.219
0.177
0.279
0.131
0.228
0.142
0.254
0.177
0.285
0.162
0.281
0.131
0.220
0.149
0.279
Table 1: Mean Absolute Error (MAE) and Mean Squared Error (MSE) on 12 real-world datasets with exogenous variables. The best results are Red , and the second-best results are Blue . Avg represents the average results across the two forecasting horizons.
Dataset
NP
PJM
DE
Energy
Average
Metrics
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
(a) Replace Variational Generator
0.537
0.464
0.140
0.237
0.548
0.471
0.226
0.374
0.363
0.386
(b) Remove Lalign
0.659
0.526
0.137
0.230
0.791
0.584
0.308
0.446
0.474
0.446
(c) Replace Graph VAE
0.691
0.540
0.213
0.290
0.665
0.526
0.228
0.376
0.449
0.433
(d) Remove Graph Refiner
0.853
0.599
0.320
0.387
0.970
0.653
0.278
0.413
0.605
0.513
GCGNet
0.496
0.442
0.128
0.223
0.491
0.445
0.179
0.330
0.323
0.360
Table 2: Ablation studies for GCGNet. The best results are highlighted in bold .
Models
GCGNet
TimeXer
TFT
TiDE
DUET
CrossLinear
Amplifier
TimeKAN
xPatch
PatchTST
Metrics
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
NP
0.425
0.377
0.440
0.383
0.647
0.488
0.467
0.416
0.444
0.383
0.451
0.394
0.520
0.448
0.484
0.435
0.488
0.402
0.457
0.401
PJM
0.133
0.217
0.141
0.229
0.200
0.270
0.158
0.253
0.140
0.226
0.147
0.241
0.152
0.245
0.175
0.270
0.139
0.223
0.148
0.243
BE
0.458
0.301
0.477
0.301
0.563
0.354
0.547
0.348
0.473
0.305
0.477
0.300
0.502
0.325
0.488
0.315
0.483
0.302
0.485
0.309
FR
0.428
0.245
0.454
0.247
0.535
0.288
0.494
0.290
0.468
0.262
0.476
0.257
0.494
0.286
0.491
0.276
0.477
0.257
0.470
0.264
DE
0.611
0.497
0.659
0.507
0.684
0.515
0.644
0.519
0.660
0.513
0.635
0.508
0.712
0.548
0.669
0.526
0.633
0.500
0.696
0.527
Table 3: Average results under the setting where future exogenous variables are not available. The inputs are ( Xendo and Xexo ). The best results are Red , and the second-best results are Blue . Full results are provided in Table 7 of Appendix B.2 .
Mask Type
Zero
Random
Models
GCGNet
TimeXer
CrossLinear
DUET
PatchTST
GCGNet
TimeXer
CrossLinear
DUET
PatchTST
Metrics
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
Colbun
0.076
0.093
0.084
0.145
0.065
0.102
0.106
0.126
0.070
0.108
0.070
0.096
0.112
0.169
0.066
0.108
0.084
0.118
0.078
0.120
Energy
0.070
0.203
0.122
0.273
0.097
0.241
0.100
0.244
0.108
0.257
0.081
0.217
0.123
0.275
0.098
0.242
0.100
0.245
0.102
0.249
DE
0.292
0.336
0.418
0.403
0.426
0.416
0.428
0.407
0.480
0.445
0.344
0.366
0.433
0.411
0.433
0.418
0.431
0.407
0.490
0.449
PJM
0.064
0.155
0.100
0.198
0.098
0.203
0.079
0.177
0.120
0.246
0.066
0.158
0.102
0.199
0.101
0.201
0.079
0.176
0.112
0.224
Table 4: Average results under the setting where exogenous variables are partial missing. The best results are highlighted in bold . Full results are provided in Table 10 of Appendix B.4 .
Mask Type
Zero
Random
Models
GCGNet
w/o VAE
GCGNet
w/o VAE
Colbun
0.076
0.093
0.094
0.140
0.070
0.096
0.081
0.123
Energy
0.070
0.203
0.142
0.293
0.081
0.217
0.142
0.291
DE
0.292
0.336
0.453
0.430
0.344
0.366
0.505
0.460
PJM
0.064
0.155
0.108
0.208
0.066
0.158
0.094
0.193
NP
0.204
0.235
0.301
0.310
0.208
0.236
0.272
0.283
Table 5: Average results of GCGNet and the version without VAE under the setting where exogenous variables are partial missing. The best results are highlighted in bold .
Figure 4: Prediction results on the NP dataset. (a–b) Exogenous variables: wind power and grid load. (c) Endogenous variables: Electricity Price. (d–f) PatchTST, CrossLinear and GCGNet predictions when future exogenous variables are unavailable. (g–i) PatchTST, CrossLinear and GCGNet predictions when future exogenous variables are available.
Appendix figures & tables8 assets
Supplementary material from the paper’s appendix.
Appendix
Dataset
#Num
Sampling Frequency
Lengths
Split
Ex. Descriptions
En. Descriptions
NP
2
1 Hour
52,416
7:1:2
Grid Load, Wind Power
Nord Pool Electricity Price
PJM
2
1 Hour
52,416
7:1:2
System Load, SyZonal COMED load
Pennsylvania-New Jersey-MarylandElectricity Price
BE
2
1 Hour
52,416
7:1:2
Generation, System Load
Belgium’s Electricity Price
FR
2
1 Hour
52,416
7:1:2
Generation, System Load
France’s Electricity Price
DE
2
1 Hour
52,416
7:1:2
Wind power, Ampirion zonal load
German’s Electricity Price
Energy
5
1 Hour
13,064
7:1:2
Battery, Geothermal, Hydroelectric, Solar, Wind
Thermoelectric
Appendix
Table 6: Statistics of datasets. Ex. and En. are abbreviations for the Exogenous variables and Endogenous variables, respectively.
Figure 5: Visualization of prediction results on NP dataset.
Figure 6: Parameter sensitivity studies of main hyper-parameters in GCGNet.
Models
GCGNet
TimeXer
TFT
TiDE
DUET
CrossLinear
Amplifier
TimeKAN
xPatch
PatchTST
Metrics
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
NP
24
0.234
0.259
0.270
0.292
0.330
0.321
0.297
0.309
0.262
0.271
0.246
0.282
0.302
0.321
0.336
0.344
0.260
0.277
0.283
0.296
360
0.617
0.495
0.609
0.474
0.964
0.655
0.638
0.523
0.626
0.494
0.655
0.505
0.738
0.574
0.632
0.527
0.717
0.528
0.630
0.505
Avg
0.425
0.377
0.440
0.383
0.647
0.488
0.467
0.416
0.444
0.383
0.451
0.394
0.520
0.448
0.484
0.435
0.488
0.402
0.457
0.401
PJM
24
0.073
0.168
0.096
0.191
0.129
0.231
0.105
0.213
0.082
0.178
0.096
0.198
0.093
0.195
0.130
0.236
0.085
0.178
0.106
0.212
360
0.192
0.266
0.186
0.267
0.270
0.310
0.210
0.292
0.198
0.273
0.197
0.283
0.210
0.294
0.219
0.304
0.193
0.267
0.189
0.273
Appendix
Table 7: Results under the setting where future exogenous variables are not available. The inputs are ( Xendo and Xexo ). The best results are Red , and the second-best results are Blue . Avg represents the average results across the two forecasting horizons.
Models
GCGNet
TimeXer
TFT
TiDE
DUET
CrossLinear
Amplifier
TimeKAN
xPatch
PatchTST
Metrics
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
NP
24
0.208
0.237
0.236
0.266
0.219
0.249
0.284
0.301
0.246
0.287
0.210
0.266
0.252
0.303
0.273
0.310
0.234
0.278
0.249
0.294
360
0.531
0.459
0.600
0.475
0.539
0.501
0.601
0.498
0.576
0.528
0.531
0.508
0.587
0.534
0.538
0.529
0.523
0.461
0.530
0.498
Avg
0.370
0.348
0.418
0.371
0.379
0.375
0.443
0.400
0.411
0.408
0.371
0.387
0.420
0.418
0.405
0.419
0.378
0.370
0.390
0.396
PJM
24
0.060
0.150
0.075
0.166
0.095
0.195
0.106
0.214
0.072
0.166
0.088
0.191
0.096
0.208
0.115
0.244
0.077
0.168
0.116
0.239
360
0.129
0.223
0.140
0.231
0.133
0.219
0.177
0.279
0.131
0.228
0.135
0.254
0.177
0.285
0.162
0.281
0.131
0.220
0.149
0.279
Appendix
Table 8: Results under the setting where future exogenous variables are available and each model uses a fixed configuration across forecasting horizons. The inputs are ( Xendo , Yendo and Xexo ). The best results are Red , and the second-best restuls are Blue . Avg represents the average results across the two forecasting horizons.
Models
GCGNet
TimeXer
TFT
TiDE
DUET
CrossLinear
Amplifier
TimeKAN
xPatch
PatchTST
Metrics
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
NP
24
0.240
0.260
0.270
0.292
0.330
0.321
0.297
0.309
0.262
0.271
0.246
0.282
0.302
0.321
0.336
0.344
0.260
0.277
0.283
0.296
360
0.620
0.502
0.609
0.474
0.964
0.655
0.638
0.523
0.626
0.494
0.655
0.505
0.738
0.574
0.632
0.527
0.717
0.528
0.630
0.505
Avg
0.430
0.381
0.440
0.383
0.647
0.488
0.467
0.416
0.444
0.383
0.451
0.394
0.520
0.448
0.484
0.435
0.488
0.402
0.457
0.401
PJM
24
0.072
0.164
0.096
0.191
0.129
0.231
0.105
0.213
0.082
0.178
0.096
0.198
0.093
0.195
0.130
0.236
0.085
0.178
0.106
0.212
360
0.191
0.269
0.186
0.267
0.270
0.310
0.210
0.292
0.198
0.273
0.197
0.283
0.210
0.294
0.219
0.304
0.193
0.267
0.189
0.273
Appendix
Table 9: Results under the setting where future exogenous variables are not available and each model uses a fixed configuration across forecasting horizons. The inputs are ( Xendo and Xexo ). The best results are Red , and the second-best restuls are Blue . Avg represents the average results across the two forecasting horizons.
Mask Type
Zero
Random
Models
GCGNet
TimeXer
CrossLinear
DUET
PatchTST
GCGNet
TimeXer
CrossLinear
DUET
PatchTST
Metrics
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
mse
mae
Colbun
10
0.066
0.088
0.081
0.145
0.063
0.101
0.128
0.134
0.064
0.109
0.070
0.107
0.115
0.176
0.068
0.111
0.104
0.128
0.081
0.124
30
0.081
0.093
0.086
0.145
0.063
0.101
0.094
0.122
0.074
0.109
0.068
0.092
0.111
0.168
0.065
0.102
0.070
0.111
0.081
0.120
50
0.081
0.096
0.084
0.147
0.070
0.105
0.096
0.121
0.071
0.107
0.073
0.090
0.110
0.164
0.065
0.111
0.078
0.115
0.074
0.114
avg
0.076
0.093
0.084
0.145
0.065
0.102
0.106
0.126
0.070
0.108
0.070
0.096
0.112
0.169
0.066
0.108
0.084
0.118
0.078
0.120
Appendix
Table 10: Results under the setting where exogenous variables are partially missing with missing ratios of 10%, 30%, and 50%. The best results are highlighted in bold .
Figure 7: Forecasting performance under varying look-back windows across four datasets (DE, PJM, Energy, and NP).
State Key Laboratory of Water Resources Engineering and Management, Wuhan University, Wuhan 430072, China · Hubei Key Laboratory of Water System Science for Sponge City Construction (Wuhan University), Wuhan 430072, China